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Interview of Frederick Seitz by Lillian Hoddeson and Paul Henriksen on 1981 March 24, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/4877-3
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Family background and early education, motivation and funding for college; math program at Stanford University, from 1928; physics studies at California Institute of Technology; graduate study at Princeton University, beginning 1932, atmosphere of the department, faculty (Lou Turner, Eugene Wigner, John Von Neumann); colloquia, Edward Condon. Development of applications of group theory, work in solid state with Linus Pauling, Hillard B. Huntington, Albert Sherman, William Hansen, William Shockley, Robert R. Brattain, R. Bowling Barnes. Betty Seitz; work with her on the text Modern Theory of Solids. Sodium band theory work with Wigner. To University of Rochester with Lee DuBridge. Centers for solid state work including University of Michigan, University of Wisconsin, Harvard University (John Van Vleck). Work at General Electric, 1935-1936, studies of luminescence; atmosphere in industrial labs following Depression, contacts with other industrial labs; association with DuPont. State of physics in 1930s, trends at solid state centers. Work on crystal defects, pigments, leading to work on germanium and, particularly, silicon; history of study of semiconductors and influences on its development such as World War II; work on dislocations and creep; work at Westinghouse Company. World War II work with Frankford Arsenal, Dahlgren Proving Ground, and Massachusetts Institute of Technology Radiation Laboratory; University of Pennsylvania, 1938; Carnegie-Mellon University, 1942, on dark trace tubes, leading to color center papers; University of Chicago work on reactors and neutron diffraction, 1943; Oak Ridge National Laboratory with Wigner; Argonne National Laboratory, solid state group. With Field Intelligence Agency Technical (FIAT), visit to Gottingen, 1945; state of solid state physics in international centers and U.S. Return to Carnegie- Mellon; diffusion theory. Pugwash Conferences; trips to Japan, 1953 and 1962, conditions and theoretical solid state work in postwar Japan. To University of Illinois, 1949 (Wheeler Loomis); John Bardeen's work, visits by Nevill Mott and Heinz Pick; McCarthyism. Development of Seitz's bibliography, changes in the study of solid state during the 1950s.
We are about to begin Session 3 of the oral history interview on Dr. Frederick Seitz's life and work mostly in relation to solid state physics. We broke off at the end of the forties last time, with a few developments not discussed. We talked about it a little bit, but maybe there was more to be said about the work which you did coordinating research in Germany along with H. P. Robertson in the creation of the Field Intel- ligence Agency....
The name was generated to fit the acronym. That was organized just as the war was ending.
What was it, Field Intelligence Agency
- Agency Technical....We were supposed to act as a clearing house for all the intelligence teams that came to investigate what had been going on in technical areas. It was much too big a job for any office of that size. It had both American and English participants. But it did provide a place for people to hang their hats when they came through. Frankfurt was headquarters, so most people who were on missions managed to pass through, and moreover, Robertson had a wide circle of friends, so we saw a lot of the individuals. As I may have mentioned last time, the Alsos group used it as a headquarters.
Goudsmit and the famous Colonel Pash, who wrote a little book on his experience subsequently.
Did you do any solid state when you were in that capacity?
No. Mainly you traveled around and visited laboratories.
One of the laboratories you visited was Bristol, I know.
Yes. I went to London and made contact with Mott, whom I'd known before the war, and then went to Bristol to see him.
Did you spend some time there?
Only a few days.
I see. And was there any solid state work being done?
No. Mott was just pulling out of military work. He had done some work on the fracturing of metals, under the kinds of pressures you get with explosives, and a few other things. We talked about that. But he was just about to reorganize his life.
I see. I gather you visited a laboratory in Frankfurt. Zerny's?
Yes. I stopped off there and met Cherny. He was one of the Famous infra-red people, and a good friend of mine, R. Bolling Barnes, who had been at Princeton for a while when I was there as a student, as an instructor or assistant professor — had worked with Cherny, and gained some experience.
Why was that lab especially worthy of a visit?
Well, first, I was in Frankfurt, and Cherny was an internationally famous person, ao I was anxious to see what had happened. He, like so many of the people, had moved their families out into the country and he was commuting. Actually he would frequently spend nights at the lab, and then go out weekends to see his family. You've got to understand, things were sort of disorganized at that stage. Frankfurt wasn't the most heavily bombed city, but let's say it was 70 percent in ruins. We just talked a bit. I also visited a radiation scientist, Rashevsky.
He was connected with a clinic and had done some of the most systematic work to date on the effect of exposure to uranium dust among the miners. And he either gave me a manuscript or let me read a manuscript on the incidence of cancer, which was not negligible at all, and made me realize that the people who had been working in the shops in the Manhattan District had had very heavy exposure, as turned out to be the case. We did not do enough of the right kind of work during the war, on the health hazards. That's what happens in wartime. I don't know whether we had many serious cancer cases, but there were certainly people who had had heavy exposure to uranium dust in shops in the Manhattan District.
Some of the other people you visited, I have listed here: Carl Wagner from Darmstadt.
Yes. He was not available, but I visited his lab. He was one of the people who were picked up. The Army had a list of names of people and sent out a kind of dragnet and put them into a place called the Dust Bin. It's an English name.
Yes. It's the English equivalent of Ashcan. These people, for one reason or another, were thought to be potential makers of atomic bombs. You know, looking back it doesn't make too much sense, but it was the atmosphere of the day. Wagner subsequently came to the United States and I think was at MIT for a number of years, and then went back to Germany. I don't know whether he's still alive. He had been a very productive physical chemist, studying transport of ions in solids. Did some beautiful research.
I've come across his name. Did he join the Party?
I don't think so. He was apolitical.
Then you visited Pohl?
Yes. I visited Pohl in Göttingen. That's where I saw Planck. I visited the lab, and as I mentioned in the Mott article, one of the people working in the laboratory, or who had been working — it was off limits at that moment — spotted me, and asked if I would help them put some distilled water in their line of batteries. They had some batteries they used for research, wet cells. So we arranged that.
I think I must have taken these notes from your article in the Mott volume.
He was also there. I talked to him.
No. He had been in Berlin. That's where Wigner had worked with him. Wigner had been his assistant, and then he moved to Göttingen just before the war.
He was working in the area of electricity and magnetism. Or was he doing some work on solids too?
He was a theoretical physicist who did not work specifically on solids, but was interested in a wide variety of things. He was most famous for the new edition, among students, of Abraham's book, the so-called Abraham- Becker.
Which I guess got translated into English.
Oh yes, it certainly did. I certainly remember using that one. Well, this was an interesting way to get in touch with some of the people, at least, if not the work that was going on.
At that time. Do you have any other recollections of the series of visits you did in that period?
Well, I visited Heidelberg, which was very close to what was then called the French Zone. But the physicists who had been there were all taken into custody, so I did not see any of them. Then I went to Munich, hoping to see Sommerfeld, with whom Condon had worked, but again, that never led to anything. During the war, I'd worked in the field of metallurgy, and I took the opportunity to visit some of the very specialized metallurgical centers. There was a group that did work on what's called powder metallurgy. Instead of machining an object, you mold it with powder and then heat it and it sinters together, as it's called. It was a very fine center for that kind of research at a place called Reutte, near Munich. Those were things mainly of a technical interest.
What was their level of technical advancement in that field, in comparison with what was going on at the same time in the US?
Well, they were very good. These fields have always had a long history.
I'm just curious whether by that time, there had been enough yet in the US to catch up, or whether that catching up and surpassing took place after the war?
Well, we did everything we needed, but they tended to lead the way in many areas in which there was pressure for economy. Things like avoiding the use of brass, which was a fairly expensive metal, and using iron or another substitute. They did a great deal of work on that. But it was partly industrial and partly for military purposes. It had a long history. Conservation.
At what point did we get ahead of them in the US? Would you say, roughly?
Well, I don't think we really got ahead of them, except in special areas like uranium research, metallic uranium research and so forth. Then after the war Europe slipped behind, but has caught up. I would say if anything they're ahead of us again.
I see, so there was just a short period.
A short period.
Maybe a few decades.
These things have always been the lifeblood of the European countries, particularly Germany, Belgium, Netherlands. The Russians have had some very good metallurgists in the course of time.
Well, then you went back to Carnegie, and part of the job was to prepare reports on the war work.
We already discussed your work at the Clinton Lab. As director of the training program.
So we don't need to talk about that. Some of the people who joined at Pittsburgh after the war included Fausto Fumi?
Who's now at Genoa. Is he worth saying a few words about?
Yes. Fausto is a theoretical physicist, mainly interested in symmetry problems, although some other things. He's a very fine lecturer. Returned to Italy, induced a number of this colleagues to come to the United States, by that time to Urbana. We had a small Italian group there. He started in at the University of Pavia, but at one point thought he would try United States again and got a job at Northwestern. He finally returned to Italy and ended up at Genoa.
I see. Was there a substantial solid state or metallurgical effort in Italy?
No, these were all theoretical people who were interested in theory of solids. One of them was Busani, Franco Busani. I forget where he is now. I met him.
He's just moved maybe from Rome to Pisa, I'm not sure. I know he's just moved from one place to another. He stayed at our house last year when we were gone, our common house.
He's a very lively fellow. The thing to pump him about is the history of northern Italy. He's quite a history buff. He may not have done much talking.
No, I didn't have a chance to speak with him in detail about it. What aspect of history?
Well, particularly the history of the Lombards. I guess he's probably decided he's of Lombard extraction.
I'll certainly do that next time.
I spent an evening with him at which it was almost non-stop, but very interesting. I happen to be a history buff. He was most remarkable.
There was a guy from Peking, Yin Yuan Lee, at Pittsburgh.
He got his degree at Illinois, then got a job either at Case or Western Reserve, (this was before the fusion,) but was never very happy there. He felt he was being discriminated against because he was an Oriental. It could be. He's a sensitive individual. When one of the windows opened, allowing people to go back to China, he went. His father had known Chairman Mao and had got into a row with him and had to flee. But Lee apparently decided he could go back with impunity, because at that stage, which was the mid-1950s, the Chinese were welcoming scientists. The Gang of Four wasn't riding high yet. People in fields like economics had a tougher time.
But he got a good job with the Institute of Physics there, the Academy, in Peking. I never heard from him at all until President Nixon visited. Then I got a postcard just saying "Hope you are well." As a matter of fact it was sent here, so he knew by that time that I was at Rockefeller. Then John saw him when that solid state team went, sent me a photograph. I met him when Betty and I went with the gang from Rockefeller in 1977. He was invited out to a rather fancy dinner with officicals, but he played it very low key.
As far as solid state in China goes, is there something worth looking into there, or were they so far behind us all along?
They were starved for equipment and all that. It was really pathetic. These are good people, bright minds, but very marginal...
Are there any other people who stand out in the solid state area?
Not in China. John can give you his own perspective. You know, Charlie Shlicter wrote this report, which you've probably seen.
Yes, but it's hard to tell from the report, who stands out, if anyone.
It was polite. These people kept up. That is, they did a lot of reading. I suspect they had lots of time. And using whatever they could muster in the way of equipment and their ingenuity, they were able to do things. We saw holograms that they constructed and so forth. But they were starved for equipment.
What about on the theoretical side?
Good work, but nothing — earth shattering.
Nothing of international class. I think you ought to tell me a little bit about the beginning of the Pugwash Conferences. That dates from about the same period.
Well, immediately after the war, Leo Szilard, who played a great role in defeating the May-Johnson Bill, decided that something should be done. I'd come to know Szilard very well during the war. (As I mentioned, Betty was teaching in Pittsburgh, and I was sort of batching it in Chicago.) We used to have dinner together several times a week. Szilard, with his very probing mind, was always trying to dope out what was going to happen in the next few years, with his own overlay of opinions, and often remarkably right. He was quite an unconventional person. As a result of that, when he decided to set up a committee which would operate out of Princeton, the so-called Einstein Committee, he asked if I'd join it. I forgot all the people who were in and out of that committee. It must have been about a dozen or 15.
I know Joe Mayer; Pauling used to come and go; and the biologist Miller. Harrison Brown was very active in it, and in fact because in a sense the pro-tem chairman. We met and discussed all these problems, Harold Urey was interested and buzzed in and out. One of the suggestions Szilard made was that there be a meeting in some isolated place, to which the Russians would be invited, off US limits. We finally decided it should be — my memory is a little weak here — I think it was Jamaica. It was agreed upon. We managed to get the money to organize it.
Harrison Brown went to Gromyko and proposed it. Gromyko waited a month, clearly to get responses from the Soviet Union, and then they turned it down. In retrospect, they were working very, very hard on the bomb, and weren't interested in having any of their scientists exposed to that kind of discussion, on what to do about nuclear weapons. The idea stayed alive, however, although I got busy with other things and didn't stay very close to it. Then, Szilard and Brown eventually succeeded in convincing this Cleveland industrialist to sponsor a meeting at Pugwash. I'm not sure Harrison Brown actually was in on that first meeting. I looked over the attendees some time ago, and I don't think his name was in it, so I suspect that Szilard may have ended up taking the initiative. And then out of it grew that series of meetings.
One of your last papers at Penn and Pittsburgh, I'm not sure I have with me now. Was it "Theory Related to Zener Breakdown"?
The avalanche, in crystals.
I was wondering whether you could give me a little bit of background on that work?
Someone had done some experiments — and I even forget who the exper- imenter was — in the pre-breakdown range, showing that there were bursts of charge, and got a spectrum as a function of voltage. I got interested in trying to explain that.
It turned out that the method of analysis was closely related to the standard breakdown technique for the Townsend discharge in gases. There were differences, you know, in a quantitative sense, but the ideas aren't very different. I guess I invented them as I went along, but in retrospect it wasn't that novel. As far as I know, no one ever picked up on that work. I don't mean necessarily theoretically, but experimentally. I don't think people have stayed interested in burst of charge one gets as one gets near the breakdown potential in crystals.
In 1949, you moved to Urbana.
And there I'm sure there's a big story, surrounding this decision to move to Urbana, the arrangements that were made, and I'd be very interested in hearing about some of them.
Louis Riddenour had gone there as dean. We were old friends, from the thirties.
Do you know when he went to Urbana? I can look that up, of course.
I would guess he went probably in 1947.
So he'd been there for a few years, probably.
I'm trying to figure out how established he was at Urbana at that time.
He got some funds through the legislature, which was at that moment very enthusiastic about science, and with Wigler Loomis offered me a job. I thought it was about time to move from Pittsburgh. We pretty well crowded the department. I brought in Ed Creutz, nuclear physicist. He was building an accelerator. The limitation on the number of jobs you could have in a department that size, which was very strongly integrated with teaching, problems — so it seemed like a good time to move. And really Loomis and Riddenour made the arrangements, the agreement that I'd have very limited course load and so forth, and have an opportunity to bring in a number of people. Wheeler had decided — did you ever meet him?
Very remarkable guy. One of the gentlemen of — I don't want to say the old school — because he thought ahead, but he was quite a remarkable person. He had held off building up the department in the immediate postwar period because he felt he couldn't get the kinds of people he wanted. Prac- tically all education had stopped at the Ph.D. level in 1940, with a few exceptions but not many, so there was a big scramble for the people who had degrees. And he felt that if he tried to build up the department at that time, he'd get too many second raters. So he held off, temporized, felt that he wanted more than high energy physics, something to complement it, and saw a good chance to build up a group.
Was it the fashion then to try to build up in high energy?
Oh yes. Oh yes.
That was the most rapidly growing area?
A rapidly growing area, yes. It was roaring. Everyone was building accelerators. See, the Office of Naval Research got a lot of money, by the standards of those days, and would allow almost any group to build an accelerator if they had competent people, so accelerators were springing up everywhere. It was the days when it was still nuclear physics, in contrast with what we now call high energy particle physics. So I went. Housing was grim at that time. The building boom hadn't really got under way, and new faculty were living in all kinds of funny places. We took that house, which was then sort of run down.
On Iowa and Orchard Sts.
That's right. But I brought most of the people who'd been at Carnegie, Mowerer and Kaylor and then Mowerer finished his work there, so things took off. There was a big boom when we succeeded in getting John.
Which was shortly after you arrived.
Yes. He came in '51.
Within a couple of years.
Then we had these visitors from all over Europe and Japan.
Who were some of the visitors? I have written down here "Mott, Pohl and Pick."
Yes. Well, they were, you know, distinguished visitors for the short term, but in a way, the more interesting and novel cases were the post-docs, people like Lidyard and Fumi and Busani, a whole group from England — I don't think I can rattle them all off — Shuttleworth was there.
I can probably find some records on this in the department some place,
Yes. I'm certain to forget some. Then John and I went to Japan in 1953.
To that Hakone meeting, is that the one?
Well, it was spread out all over Japan. We started in Tokyo. We went up to Lake Akoni. We went down to Kyoto.
You and John Bardeen?
I think we were the only ones from Illinois, but it was a very large meeting.
Tell me more about it. I'm interested in what was happening in Japan in solid state by then. If you mention the centers where you stopped off...
Someone had suggested to the Japanese that in order to get back into the swing of science, they ought to have a big international conference.
This was 1953?
1953. They made a big thing of it. They got a little money from the government. They got a promise from our government that there would be help. Then they built it up to the school kids, and the school kids would come in with their pennies and they'd collect money from all over the country, so it was a big psychological public relations deal. They flooded in from Europe and the United States. The two fields that got the most attention were high energy physics, because of Yukawa and Tomanaga. And then solid state — on the theoretical side they were beginning to take an interest in that.
As a matter of fact, I remember one night, my book had been made available and was very widely read, and I think there were as many young people in Japan at that time as there were in the United States as a whole interested in theoretical solid state physics, and I think I met most of them. You just had to call it off about one in the morning, because there would be a long line waiting to show you some manuscript, which was often very hard, to comprehend.
How long did this meeting last?
Well, I left at the end of two weeks. I think John stayed on another two weeks.
These were meetings over a period of at least a month, then.
Almost every day or every day?
Oh yes. We were on the go. Of course, you know how the Japanese are. You take a day off and look at the scenery. So they intermixed pleasure with business. You had a chance, in a place like Kyoto, to see them printing silk, all these things. In retrospect, it was an absolutely exceptional experience.
To go to Japan in 1953 must have been a little bit like going to China now, because they hadn't yet built up after the war. At that time they were still very backward.
That's right. Well, there still were enormous amounts of destruction around. They hadn't had a chance to rebuild. There were many seriously wounded war veterans and cripples, around begging. You saw beggars in large quantities with tin cups. It was not quite as shattering as the 1945 period in Europe. Of course, you were then closer to the war. Eight years had elapsed. But nonetheless, the evidence was still there.
Did people have enough to eat by that time, most people in Japan?
Marginal. Marginal. The school children looked fairly healthy, as though somehow special means were being taken to keep the kids going. Of course their fishing fleets were operating, and fish was one of their major sources of protein. In addition, we were doing our best to keep them from going Communist, and as a result doing special things to help them. It was a result of the MacArthur policies that set in soon after the war ended.
It isn't like India, where you see people, just bag of bones nothing like that — but a great deal of hardship. We met the academic people, we met the industrial people, and we met the politicians. I was much impressed with the fact that they were often closely interrelated. That if you sit at one of those big round tables, and professor's wife is related to a wealthy industrialist or a government official. They were very family conscious, and the families tended to break into specialties, as you went down the line.
What about theoretical solid state physics in Japan?
Well, it was coming along. There were many people doing theoretical work who would have preferred to do experimental, but they didn't have the means. If you went into a laboratory, it was very much like a Chinese laboratory now, rather spare, some equipment that they'd managed to rig together with ingenuity and spare parts. One of the things that happened to those who came to Urbana — there were two Suzukis, as I recall — when they saw the wealth of experimental material, they dropped their theoretical plans and went into the laboratory. And of course, by the end of the fifties, they were beginning to be supported pretty well back home.
Incidentally, one thing to realize is, by 1953, the concept of the transistor was already abroad, and there's little doubt that the industrial people there had decided they were going to go into electronics; that is, it matched what they needed. You could go a long way with modest resources. I also was taken into an X-ray machine factory in 1953. It was comical, because they had no concept of standardization of parts. Had a big set of drawings in the middle of a large room, and then they had machinists, instrument makers, in cubicles around this room.
Each man was making an X-ray machine, and would go up to the drawing and make a measurement and go back and make a part, and these things would come together. When I visited again, which was seven years later, I was taken to the same factory. By that time they had an assembly line. So they were learning an awful lot about modern industrial practice, for the civilian economy.
One of the aspects of Japanese solid state physics that struck me recently was that there is much less interaction between the academic solid state physics and industry, in the sense that they don't seem to hire PhDs in solid state in industry, as is done here all the time. I was wondering whether there was some explanation for that that has historical roots, or whether this is just to be found in industrial policy in Japan now? But it seems to me something that probably slowed them down. And probably continues to.
Well, if I look at the competition they were offering us, it's very much the technological side, and I think that's where they're putting their money. I think they feel that the ideas that they want to build on, you know, the theoretical ideas will come to them one way or another, and they want to be darned sure their people are practical. We've had waves of that in the United States too. Bell Labs has maintained a fairly steadfast policy, but places like Westinghouse and General Electric have oscillated from time to time. General Electric had built up its laboratory to a very fine level in the early sixties and then practically took it apart under Cordner and is now trying to put it together again.
So they may have some oscillatory phenomena. But I must admit that it's rare for the friends I know to be consultants to industry in Japan, those who are in academic work. If they do it, they don't talk about it. It could be that that period of turmoil led to an estrangement. You know, the troubles in the universities ten years ago, far worse than our own. And it could be that at that time there was a kind of a divorcement. Now the industrial people are very suspicious. I have a feeling that's died out, although there's still a very large amount of left wing thinking among the Japanese academics. You probably know more about that than I.
It's difficult to get clear information about that. I certainly got some, but it was never very well explained to me.
Remember the National Science Council in Bueno park — did you ever have any association with them?
No. You mean the Japan Science Council?
Yes. You almost had to be a very strong left winger to get elected to any post in it. But what I'm speaking of, however, is 15 years out of date. I just haven't stayed that close to the Japanese scene.
I've heard this also from my studies of accelerators in Japan.
Yes. I had one experience that was sort of amusing in its way. When I was president of the Academy, I visited Japan. I was on my way to India, to a meeting of International Union of Pure and Applied Physics that Bhabha had arranged. I stopped off. At that time Yukawa was our only Japanese member; Betty had never seen Kyoto so we went down and paid a visit. He gathered a group of young colleagues together, and they said, "Let us start by talking politics." I said, "Well, I'm not here on a political mission."
Could you give me the date, roughly?
1962. It may have been '63. I know we were in Japan on Christmas day. They said they were very unhappy that our country was preventing them from developing normal relations with China, and they wished it would stop. This was, of course, the period when we didn't have very close relations with China. And I said I sympathized with them, that before World War II we had been much closer to the Chinese than to the Japanese, and it was with our regret that the situation had been reversed. So, we quickly got off politics. But it was clear, the group around Yukawa were very left wing.
Well, Sakata is known to be.
And Tomanaga. And Takatani, especially. They all are well-known left-wingers.
Yes. They must feel in a vacuum now because the Chinese are very popular with everyone.
Back to about the early sixties in Illinois, I think it was in the Mott article also that you mentioned close relationships between the University of Illinois people at Chicago, including Cyril Smith, Zener and Lawson?
People at Cornell, including Robert Sproul and James Krumhansl. And people at Purdue, which included Fan and Mark Horowitz.
I was wondering how these relationships were established and supported?
Well, we used to visit one another a great deal, give colloquia, invite people back and forth. You know how physicists are.
Short visits, one day or long visits?
One or two days. I almost went to Chicago at that period. There was a big explosion at Urbana, on the campus, and the president was fired. What had happened was, a member of the board who had been very loyal to the university got the idea in the McCarthy period that he could gain prestige within the state by accusing some of the administration of being soft on Communists and so forth. It never worked, but there was a turmoil. The president was fired and there was a two year hiatus in which we didn't know where we were going. At that time I got an offer of a job both at Chicago and at Northwestern, which in a way were very attractive, but then neither place was in a position to build up any substantial group, so I decided to stay. I think John was in somewhat the same situation, although John is a little less sensitive to external events. But the campus was in a bit of an uproar.
I didn't even know about that.
Yes. Henry was finally made the president, and everything settled back.
Let's just scan a few of the papers. I'm not going to go into the content particularly, because most of the papers are very clear. When we're actually writing, we may come back and ask you questions, but I'm going to focus on some of the connections, things that aren't in the papers themselves.
The Theory of Diffusion paper seems to have been stimulated by a 1950 paper of Zener which criticized the earlier work you had done with Huntington on the subject in 1942 and 1949, in terms of magnitude. He suggests here an interchange mechanism to compete with the vacancy mechanism.
In what material was that?
Copper, yes. In the salts one could determine the mechanism quite easily, but in the metals it remained an open question until Simmons finally did some very ...
This is Ralph Simmons?
Was he by then at Urbana already?
I think Simmons was one of our students, and stayed on. Ralph began doing these careful measurements of X-ray constants and density, as determined by length of the bar. And this pretty well settled the diffusion mechanism; it depends upon vacancies. But at that time, people were still rowing. Generally speaking, if there was an ambiguity, you'd find people taking all possible positions. Which is what makes the wheels turn.
The Kirkendall effect experiments, they seemed to be the critical ones in this field.
Yes, there was a chap named Kirkendall who observed that there were boundaries that moved when two metals interdiffused.
Where does he work?
I think that he was a metallurgist perhaps in industry. Not a major figure, but he did the one experiment which became quite celebrated.
It's mentioned in half the papers. Setiz: Yes. I don't think he persisted.
We'll have to look and see how he happened to come to the technique.
Well, he was studying interdiffusion of metals and observed that an oxide boundary moved in a certain way, relative to the point where the gradient was 50-50 between the two metals. This was a matter of much interest. David Lazarus was involved in these things, too.
I probably ought to talk with Dave Lazarus about this subject too. Zener's name comes up an awful lot, and I will have a chance to speak with him next week.
I'm glad he's relented. I wanted him to go to Europe as part of the Mott team, but he wouldn't.
Well, he said that he'll spend as much time as necessary, and I'm very much looking forward to it.
He's done an enormous amount of work.
Oh yes, he's been very creative, very imaginative and stays imaginative.
His name comes up in many, many papers.
He did precision measurements by a variety of techniques on diffusion on carbon in iron, quite a classic piece of work; probably more decades of measurement of the diffusion coefficient than anyone else.
He seems to have been both a theorist and an experimentalist.
That's right, yes. He got caught in that box which bothered me in the late thirties, to realize that the field couldn't progress unless there was a large number of experimental people. Whereas I tried to build up a team, he began doing experiments himself. He's very much an individualist, as you'll recognize when you meet him. It isn't that he hasn't worked well with students. He's very loyal to them. But he's got some of the aspects of a loner. He went to Westinghouse, was actually director of research for a while, I think, and then eventually took a job at what's now Carnegie Mellon, and I think is still there, working on government contracts.
That's certainly where he is now and where I'm going to interview him.
His program centers about trying to get energy from the thermal gradients in the ocean. He's prepared to tackle almost any field, very courageous, imaginative.
He started out pretty early, too.
Yes. Hoddeson; In the thirties, there are papers by him.
Late twenties. He was an undergraduate at Stanford. And then I think he did his graduate work at Harvard. Perhaps with Bridgman. Got his PhD around '29. Spent some time in Europe.
I'll know much more about that in a few days. On the generation of vacancies by dislocations and vice versa, there are a couple of PHYS REV Letters. Is this the beginning of that work relating the dislocations and vacancies?
Yes. There was some strong experimental evidence for it, that when dislocations move they leave a trail of vacancies. It's probably an important effect, but people just aren't interested in those things, as far as I can tell, any more. The literature now is so voluminous that even though I try to keep up, it's hard to do.
A couple of names of people come up again and again in these papers on this subject. If they're worth commenting on, then maybe you could say a few words, but if they're relatively minor, then we should go on. Smacula is one of them.
Yes. He was a colleague of Pohl, came to the United States on what's been called Paper Clip, the group of people that were brought to the United States by the services in the '46 - '47 period to fill out some of the military laboratories, and who eventually dissolved into the American scene. Wagner was of that kind. He got a job at MIT. And as a matter of fact, Smacula I think also ended up with von Hippel at MIT. Very competent experimenter.
Von Hippel had a whole group around him like that. He's one of the people in that Cambridge area who ought to be interviewed, yes.
He (von Hippel) had a son at Princeton who's interested in political aspects, John is it, or Frank? Von Hippel married James Franck's daughter, you know, the famous physicist. So the young von Hippel had him as grandfather.
There are groups of experimentalists; they include, for example, Juli.
Yes. July was a Hungarian. I'm trying to think of whether he by chance visited the United States. These were people who did experiments which, at the time, seemed to be very important.
Yes, in Hungary.
So then there was something going on in Hungary that was not negligible.
At least in this areas of imperfections. Seitz; Yes. July and Hartley. I think Hartley was a student of Juli.
On the centers in alkali halides, there's a Letter in 1950, then later there are the papers on it.
These are the ultraviolet bands which you get if you have a halogen rather than a metal excess.
And the issue here is the model. Is it a whole attracted or an isolated positive ion vacancy, or is it as you suggest, two centers which are composed of two positive ion vacancies, to which one or two holes are attached? Was this a central issue?
In a small group. It started in with the guardian work on F centers and Mott's involvement. Then during the war, we did these experiments on electron bombarded layers of the salts, observed that there were bands off in the ultraviolet. After the war a lot of work was done in certain circles trying to resolve this. I think a lot of the stuff I wrote turned out not to be right — not that the experiments were wrong, but the interpretation was wrong.
Huntington and I had done some calculations and reached the conclusion that the paired vacancy was very mobile, that is, the positive negative ion pair. On this assumption I built a framework. I think it's pretty well agreed now that it's not mobile. There are areas of this that are simply not understood. There's some entity that is very mobile, because you get effects that are clearly connected with ion migration at room temperature, but what it is has never been settled. After a while people lost interest and got off into other directions. I think what happened is that the excitement surrounding semiconductors captured the attention from other problems which don't have anything like as immediate a practical interest.
I'm interested in this connection to the war work. Electron bombardment? Why were experiments of that sort being carried on during the war?
Well, the story is as follows. The radar screens which were used were luminescent screens, so they had to be viewed in the dark. While you could develop luminescent materials which would glow for a period of time after they were evanescent, the Navy wanted something that could be viewed in normal daylight, because they didn't want the bridge to be dark during daylight. They wanted to be able to see if they were going to hit a whale or something, I think. So there was a great deal of interest in developing what were called dark trace tubes. The Germans had done a little work on this using alkali halides, which appeared in the literature, and it was picked up here.
The English had done some work. I think the English called it the Skiatron. But Bob Mower and I started a program in Pittsburgh on this subject. The goal was to try to find out what materials darkened most favorably. Potassium chloride was eventually the one compound of choice, because the darkening curve matches the eye sensitivity curves, gives the maximum visual effect. You also want to be able to bleach it, so that you can use the screen again and again. We did a great deal of work on that. So out of that came an interest in these discolorations. It's an interest we had all along, but there was a natural wedding of our interests. We left all of that work, as far as I recall, back at Pittsburgh when we left. It continued there for a while.
By other people.
Yes. The wartime work was left behind. Bob Mower must have a pretty good memory of all that, because he was in the thick of it.
We've talked about it a little bit but haven't completed the discussion yet. This is related — the influence of plastic flow on the electrical and photographic properties of the alkali halide crystals. Oh, what was the controversy in the 1930s between Smekal and Ioffe? Is that something that we should go back to?
No, it belongs to the dark ages. The Russian physicist Ioffe was very much part of the international scene in the 1930s before World War II began heating up. There was a physicist Smekal who, I remember, visited Urbana in the early 1950s, who'd worked in the field of the imperfection induced properties of solids. There were arguments back and forth. I think Smekal believed that the effects were mainly what we now call intergrain boundaries. It's not an issue which is hot any more.
But it seems to have led to a lot of interest for a while. By 1950 there are new experiments, and the whole subject can be put in a new context. Now, there's a short paper, which doesn't fit in with most of the papers here, on the theory of resistance of a cubic semiconductor in a magnetic field. That is on a somewhat different subject. Or maybe I'm wrong?
No, that's probably related to the Hall Effect.
Well, there's the early work of Ganz in 1906, based on the Lorenz theory. The paper is basically a discussion of the work of Davis, which you expand and explain. Apparently trying to make it usable to experimentalists, I think, but you find it doesn't fit all that well. I don't know if it's worth spending time on.
I think this is related to the Hall Effect. You know, you get cross fields if you have a current flowing in a conductor. This was an attempt to work out the classical theory. I took cubic symmetry because it's the easiest of all to work with.
There's a paper on the energy states of impurities in silicon, and this paper is a 1951 paper, which —
That's with Castleon.
Yes, it was Castleon. Who is he?
He is a physical chemist who I think currently is at Catholic University in Washington. I think he cam from Catholic U and spent a year or two with me in Urbana.
Here you question the work of Pearson and Bardeen.
Did I dare do that?
Yes. They suggested the ionization energy in silicon decreases with increasing impurity concentration, due to an attraction between impurities and the free carriers. But as you point out, there's evidence that the ion energy depends on the density of impurities but not on the free carriers, and so this whole thing you question. The paper doesn't supply a solution, but it just raises the question.
Again, this is something that doesn't fit into the mainstream of the other papers that you have.
It was one of those things that was a hangover. They had done some experimental work and we tried to interpret it, I guess never got far enough. Castleon has become an excellent teacher and has written a textbook on some aspect of physical chemistry.
The question of understanding the way impurities in silicon and other semiconductors work, how doping works and so on — I gather a lot of progress was made on that during the war. That came up in my dinner conversation with Morrel Cone. He feels that Bell Labs has been over-emphasized in that respect. They feel that they did the major work there, and I was wondering how you felt about that? I gather Cone feels that important work had been done, for example by Bob Sachs, in understanding this.
Yes, Bob did work. Bob was with Lock Horowitz for a period during the war. And they did some very fine work. One shouldn't try to under-estimate the contribution of the Bell Labs. On the other hand, there are lots of people worrying about these problems. Sachs was one.
Were there some other people I should know about? I hate to leave out the people who are not as powerful as Bell Labs, who did equally fine work that may not have been as well advertised.
Incidentally, Bob would be a good person to talk to, if you haven't, about the Purdue era. I don't know when he left Purdue, but he was certainly there up through the time that I went to Pittsburgh. I suspect he may have been there throughout the war. Bob has got off into other things. He was actually director of Argonne for a while, as I recall. But he would remember that period. I think Bob may have been a student who worked with Teller. I have a feeling that he was in the Washington-Baltimore area before World War II.
I'll do that. He isn't too far away. He's at Chicago now.
That's right. He moved back on the campus.
So he's easy to get to.
Lock Horowitz was always sort of possessive of his research. I know Bob and our gang were very close for a period, but then we'd see each other at meetings during that wartime period, rather than in each other's homes in the laboratories.
Were there other people like Bob Sachs who were doing major work on that subject that I ought to know of?
The group at the Radiation Lab were interested in most of the things that were either wartime or immediately post-war, up through the period covered in that book. It would appear in there.
In Cory and Widmer?
In some way or other. The Bell Labs work got going in force really after the war. They did some work during the war, but mainly after the war. The sequence of papers by Shockley, probably '47 or '48, in which some very careful work was done on doping. By that time, most of us had got off into other things.
Then, the review of the progress of physics — this is an historical view in the JOURNAL OF THE FRANKLIN INSTITUTE.
I think I was just asked to give a lecture there. It got written up.
It's something that helps me in thinking about how to organize our book, but perhaps we needn't spend any time on it now. Now come a series of excellent reviews, with just a few papers in between, one of them on "Fundamental aspects of diffusion in solids." This is an overview of the entire field. Here, you lay out all the early work that was done by Frankl and Wagner and Shockley and Chaki and Zener and Bardeen and later work by Bardeen and Herring and a whole cast of characters, Panet, Navarro, and also the experiments.
Where was that published? Hoddeson; This was published in a book.
Oh yes, one of those.
PHASE TRANSFORMATIONS IN SOLIDS.
That was one of those Wiley books.
I usually tried to be as comprehensive as the situation permitted.
I was very struck by the incredibly close interplay — this is something that's true all along — interplay of theory and experiment in all of these areas. I didn't realize how important the reaction rate theory of Wigner and Iring was. I would have asked him about it.
Yes, that was a very important paper. The ideas, I suspect, were almost all Wigner's, although modesty prevented him. The person who took off from it was Iring, who wrote a very big treatise generalizing the technique, but the core ideas were in that paper.
We'll be reading all these things when we're writing. Rather than ask you the details now, I think I'll probably come back and ask you detailed questions on that. Let's see, this is "Speculations on the properties of the silver halide crystals." Here also you lay out the whole field, what's known and what isn't, problems that need to be worked on.
Yes, I tried to beat the drum for getting the, at that time ONR and these military agencies — the Science Foundation wasn't very rich yet — to support a good deal more work in the silver halides, because we didn't know very much about them. Some of the gap has been filled in the meantime.
Had they been working on the silver halides already in Europe?
Yes. Wagner and people like that were doing experiments. And Mott of course had done a great deal of work on the theoretical side, with the darkening that you get in photographic emulsions.
You thank Mott for extensive discussions during his visit in the fall of 1950.
Did he stay at Urbana for a length of time?
Yes, it must have been a month or two.
I see. That's long enough to do —
Yes, I think we put him up in the Union. I think he had a lot of fun, wandering around. He discovered a lot more on the campus that I had. Of course, he was a free agent.
Did he cause people to do experiments that they might not have done otherwise?
Yes. He loved to discuss experimental work. I know he found some people in mechanical engineering who were doing some exceedingly interesting work on what's called fatigue. If you take a metal bar and stress it beyond the elastic limit long enough, it will eventually break. These people were doing some very good work. I didn't know it was going on.
Color centers in additively colored alkali halides, crystals containing alkiline earth ions. These are based on experiments and interpretations of Pick and you also thank Pick at the end. Was he also at Urbana during this period?
Yes, he was with us for a couple of months.
So once again, he was able to work and talk to people.
Pick was still at Göttingen as a sort of chief deputy, and we all thought he'd follow Pohl, but instead, the job was given to filch, who was a very ingenious experimenter. Pick went to Stuttgart, which was a break for him, although he may not have known it at the time, because it gave him a chance to build up a real center. Stuttgart's much more prosperous than Göttingen.
Did that center grow up around Pick?
In solid state, oh yes.
It definitely did?
Yes. He started in a bombed out building, and then everything took off. I remember visiting him in Stuttgart. You tried to find where the streets were as you went through all this debris of partly bombed out buildings. But the state of Württemberg became quite wealthy and was able to put on a good show. The province that Göttingen is in was cut in half by the Soviet zone border and, as a result, has never been as prosperous since the war. They get federal money, but those institutions depend in part on money from the equivalent of a state. You know, what they call the Land.
This paper on imperfections in nearly perfect crystals is again a synthesis and very clear, an attempt to interpret almost the whole field.
Yes, that was another symposium, and I guess also published by Wiley.
Wiley had a very gung-ho man in charge of science at that time. Tracked all the meetings. I think they got much less enthusiastic as time went on.
Who was D.L. Dexter, with whom you worked on the effects of dislocations on mobilities in semiconductors?
David Dexter. He's at the University of Rochester. A very earnest, interesting person. I forget whether he came out of Cornell or not. He had a period of illness, ten years later, a kind of breakdown, and I don't know how he is now. But he would be worth checking. I'll tell you, ask Mower how Dexter is, because Bob stayed in touch with Dave. He was a very good person. Dave came, I think, from Cornell, but I'm not sure. He spent a couple of years with us and then went to University of Rochester. As a result of him, we had quite a sequence of people from the University of Rochester who came to work with us, one way or another.
There was Bob Knox, who went back to Rochester. I don't know whether he's still there. Perhaps. I haven't heard much of him. Al Gold, who returned to Rochester and then was here as one of our vice presidents, now is provost at Polytechnic Institute in New York, which was the old Brooklyn Poly. There were others too that came. Bob Mower grew up in Rochester and visits there, because he has relatives, and stays in touch with those people, so he'll know more about the state of the union than I. I occasionally get a letter from someone there.
Mower is very interested in the project now, is clearly going to be very helpful and cooperative. Another paper on the plasticity of silicon and germanium. Now, here you analyze the data of a man named Gallagher. Is he a major figure?
No. He may have done some work on plastic flow, elevated temperatures. We worried about it.
Here's your excellent PHYSICS TODAY article on the radiation effects in solids which will help us. I'm wondering where to put this subject in our organization.
Well, it has to do with defects, although it stands alone, because one is interested in what radiation does to solid materials. It was one of the big problems, as you remember, in connection with the reactors that were built during the war.
Right. I very much appreciate all the history in this particular article. Very useful. Both Mower and Taylor will be able to help with this as well.
Then we have a big article on "The Generation of Vacancies by Moving Dislocations." This was another one of your reviews which help people starting in the field learn what's the state of the art.
Was that published in the English journal?
ADVANCES IN PHYSICS.
Yes, I guess that was the start up of that, of Mott's Journal.
Oh, is that Mott's Journal?
I think so. ADVANCES IN PHYSICS looks like English type printing. What volume is it?
Yes. He decided that he ought to start a journal and I was asked to send a manuscript.
I know that journal. When I was a graduate student, I was reading papers in that journal by Pippard.
Yes, sure. By that time Mott would have been at Cambridge. think he went to Cambridge in '54.
Well, this is '52.
I meant when Pippard was —
Oh, when Pippard was writing. Yes. Let's see, there was a reference here to T. Bluett. Seitz; Tom Bluett was one of Jim Kaler's students.
Tom ended up working at Argonne.
I see. He was at Oak Ridge.
He may have spent a period at Oak Ridge.
His name comes up very often in this area.
I think Tom started with us at Pittsburgh, and may never have been at Illinois, and then went to Oak Ridge and ultimately to Argonne, but again he'd be in AMERICAN MEN OF SCIENCE. In addition he and Jim Kaler were very close friends, family-wise.
Tom visited me once here, about ten years ago, and as I recall was somewhat at the crossroads, on what he would do next. So I don't know where he is.
I see. Is he someone we should have on our mailing list?
Talk to Kaler.
You refer to experimental work done by Molinar and Orts at Delft. And in Dreyvusteyn Laboratory. Was that a major laboratory?
It probably was. What does it relate to? Dreyvusteyn was very famous in his day, yes, but I forget the experiment. You know, the names ring a bell.
Well, there are many experiments mentioned in this article, Cumon and Drayer, Miss? and Saches. It was to do with —
— the effects of plastic flow on copper.
Yes, and they seem to have improved the earlier work of Juli and Hartley. So, I'm just trying to get a feeling for where you know — the pockets of work that are springing up.
Well, Molinar and Ortz worked on plastic flow, as I recall, and how it anneals as it went up as one went up in temperature, recovery and so forth. I don't know whether they've continued, because this is sort of a catch-all paper which tries to tie the thing together.
Well, I always look at these papers, these large cathch-all papers, as you call them.
The footnote references give one a feeling of how the stuff pans out.
Yes, but also they lay out the beginning of a new subfield. Your big solid state book in 1940 laid out the whole field of solid state physics, and now, these review articles are sort of the treatise which starts the sub-field. In many cases, it brings it together, and they're very important in that regard. They give students something to start on before becoming a specialist in a particular area, just as plain old physicists could read your book and then go on and become solid state physicists.
I don't know who works in this field at the present time.
I guess we can talk about that later.
Kaler may know, although I don't know to what extent. He's sort of pulled himself into a cave, in the intervening period. But I think he stays in touch with a substantial part of the family of people who work in this field, particularly the radiation-induced defects.
This paper on imperfections in silver halides seems to be one paper resulting from that meeting you were discussing earlier. I know that Mott was there.
Yes. That was that big meeting in Japan.
Did just everybody who was important in solid state physics go to that meeting?
If they could get travel expenses.
If they could get travel expenses.
John and I, as I recall, went over courtesy of the Air Force. I remember we stopped at an Air Force base for 24 hours, in Hawaii. I gave this talk at Okoni. It was sponsored by Fuji Film. We were there several days and never saw Mount Fuji at all. All we saw was fog. It was September.
Fuji is hard to see. When it comes out, it's dramatic.
I fled Tokyo as a hurricane was approaching. John stayed on and went through the hurricane, but I remember looking back from the plane. As we got up above the clouds, I could see the top of Fuji, but that was the only time in all those days. We were there.
We saw it on our last day in Japan. We hadn't seen it until then, in four months, but on the last day, we were taking the train to go to the airport.
That was probably January, wasn't it?
Early January, well, that's the time to see it.
It was spectacular. It's really wonderful. The next time I go to Japan, I'd like to climb up to the top, at night. I hear that's wonderful.
Do they have lights?
I guess so. I hear that's a wonderful thing to do. Very romantic, and it's not a difficult climb. Here's another big review article which I think we just simply have to study, rather than to ask you about the details.
Yes, I think it's made out of date by the work of a man named Barley. In part, not as far as experimental stuff goes, but I think the interpretation —
Where does Barley work? Seitz; Barley is probably now at Harwell. But he was the one who proposed that when one irradiated basic material, that excited halogen atoms would jump into interstitial places. And I think that has turned out to be right. It's called the Barley Mechanism. A namesake of his who's a big shot in the British government, whether it's a relative or not, I don't know, but it's not the same Barley. I suspect you'll find out that, through Lydia. Incidentally, before you leave, we've got to get you Lydia's name and address. When do you go to England?
Let's see, I'm going first to Erice on the 19th. Hans Bethe is going to be there during that entire stay, ten days in Erice, so I'm going to ask him about the Bethe-Sommerfeld article and a little bit about his wartime work. And then, on the second, I will fly to England. Gordon will come home and finish the semester, and work there, from the 2nd until the 17th.
Of what, May?
May. Then Gordon and I are going to meet on the 17th in Paris. I'm going to stay for just ten days. He can stay for a month.
Is Ikiki the one who arranges those at Erice?
He asked Wigner to organize one in the whole area of arms control, and wrote to me asking, through Wigner, asking for names, and I sent him a list of people. And then I never heard from him for about 2 1/2 months, and then got a very nervous letter from him last week, to try to run down Wigner, who I think is at Baton Rouge. He likes to go to Baton Rouge this time of year.
I get the impression Ikiki is a character.
I ran a symposium on the history of particle physics at Fermilab last May, and Ikiki was supposed to be around at Fermilab for another reason at just that time. When he heard about the symposium, he changed the dates of his visit by a few days, which made me think that maybe he was trying to avoid some people.
I think I met him at the Volta celebration. He's a rather stocky?
I haven't met him yet, but I'm sure I'll meet him. I may not bring up the Fermilab symposium right away. I mean, I was just told about this. It had nothing to do with me at all.
Wanted to avoid his enemies. It's a little like the Cosmos Club. It's a great place to see people you want to see, but also you bump into a lot of people you'd rather not. It was sort of peripheral to war work, although in that NEW YORKER review —
Jeremy Bernstein's article on Bethe. Seitz; — you find a reference to some work he did for Frankford Arsenal. I was then working with the people of Frankford Arsenal on armor penetration. A paper which got classified, although he took all the data out of the ENCYCLOPEDIA BRITANNICA. I forget whether it was done on contract, probably was, but he prepared a paper on the mechanism of armor penetration.
He mentions it in that article and even mentions the fact that I was linked. But at that time Bethe was not cleared, and he was amused because he wasn't permitted to get a copy of his own paper, because he wasn't cleared, and Frankford Arsenal put a clearance on it. Then he was taken to the Radiation Lab, where he worked on crystal rectifiers, and wrote several papers, those that you've seen.
The ones referred to, yes. Which as I say, I have not been able to find them any place yet, but they're probably at MIT somewhere.
Assuming the records are kept. Then he was called to Los Alamos and spent the rest of the war there. But I remember, at one of our meetings on crystal rectifiers, he appeared and talked about the views on how the rectification mechanism worked.
Were his papers major in the field?
Well, like everything he does, they were excellent.
I first heard about them in Japan . I presented my little paper on the transistor at a meeting of historians a year ago and in the discussion, somehow the Bethe paper came up. They were aware of it, and at that time I wasn't. Then I went back and tried to find it and so far haven't been able to.
Well, he worked on the problem of a point contact that was rectifying, how the current would flow, and so forth. I'm speaking from memory. Hoddeson; I remember actually discussing the concept of the spreading resistance with Bethe last spring briefly, because that had something to do with my transistor paper.
That's right, because the early transistor was a point contact.
Yes, right, and he knew all about that, so I guess that related somehow to this work.
That's right. Bethe was, still is, an incredible person. They say that he would sit in the library when he was writing these papers with Sommerfeld, and just write it page after page, with another pad to do all the calculations, and it was essentially set. You know, it went through the typing process, but went on to the printer.
I'm sure it's going to be great to go through that one. Here's a paper you wrote on Fermi statistics and its applications, with Bethe presiding. This was a meeting in honor of Fermi.
Oh yes. That was in Washington.
Yes. This is an historical paper, which goes over some of the material actually that I went over with Gordon in my little piece on the electron theory of metals. But it goes a little further, and of course I'll have to go further in the book that we're now planning. There was a question I had that I still haven't answered, having to do with the relationship between Dirac's theory of holes, positrons, and the theory of holes in semiconductors. They seem to come out about the same time. I guess in the context of semiconductors, Peierls really had the concept first, but didn't expand on it and draw upon the analogy, didn't bring in the hole in the Fermi sea.
Peierls wrote a very long paper, I think in the ANNALEN DER PHYSIK. It must be 80 pages, on the anamolous Hall effect, as I recall.
There's one that's not that long. I'm not sure.
Those things tended to be around '28, '29, '30.
Well, this paper I think is the first paper on the Hall effect.
A brief one.
Yes. Then there's another one, you say. Well, I'll have to go look at the other one. The question really is, where the hole is, first. There is a paper by Heisenberg in 1931 that I've looked at, which does have the full picture, which is almost like the Dirac picture, in another context. This paper by Heisenberg here in the ANNALEN DER PHYSIK is really a paper that discusses the Pauli principle and how it provides closure in certain examples, and he discusses holes in semiconductors.
My guess would be that perhaps the concept of the hole and the positron came along somewhat independently. And Heisenberg would have been familiar with Dirac's work, and then saw the application. Heisenberg had this very wide range of interests, something like Bethe. I remember, there was such a thing as the anomalous Hall effect.
In this paper that Heisenberg writes, he does not make the comparison with the Dirac theory. The Dirac paper on the discovery of negative energy states, as you mention here, is a '28 paper, but the model of the positron as a hole in an infinite sea of negative energy states doesn't appear, I think, until '31. So there's a similar —
— a hiatus there.
A similar gap of a year or so before the full interpretation somehow sinks in, and the real question is whether there was any interaction between these two concepts that were evolving in two different areas at that time. I suppose Peierls would know.
Peierls would probably know. I know that initially, Dirac thought that what we now call the positron was a proton. And I think it was Pauli who said, "This cannot be, it would have the same mass as an electron."
Weil. Seitz; Was it Weil? Someone did.
Yes, he showed that it couldn't, and I guess there was some work by Oppenheimer. Seitz; Yes, and then Oppenheimer.
I think there was an important paper by Weil right after that.
This was an enigma. And then Anderson discovered the positron, and the thing made sense. In the meantime Oppenheimer had written a paper on the generation of pairs, before they were observed.
Right. But as far as you know, was there any interaction? You have looked a little bit into this literature as well. Is this something I should pursue further? It's very curious.
I think you have hit a theme that is worth looking into, to what extent there was interaction. Heisenberg was often interested in what one might call quite mundane problems. You know, he wrote papers on ferromagnetism and things like this. If he had an idea obtained from any direction that resulted in an application of quantum mechanics, he'd pursue it. My guess is that he wrote his paper, just a guess, at a time when the business about positrons was getting cleared up, and said, oh gee, this is a possible explanation for anomalous Hall effect.
It's a curiosity.
It's a curiosity. Well, those things are interesting.
Right. Theory of the Kirkendall — who's Darkin? Darkin comes up all the time.
Darkin was a metallurgical physicist, worked for US Steel, did some work on diffusion and related things. Very competent person, no longer alive, died a few years ago.
This paper on the theory of the Kirkendall effect in '55 — we're getting to the end of our time span now — published in Japan Physical Society JOURNAL. Was that also the result of a meeting in Japan? Seitz; I wouldn't be surprised. I think it's a digest of a paper that was published in CRYSTALLOGRAPHICA ACTA.
I see. I don't have all the papers here. This is a non-scientific paper — "Relationship between dislocations and vacancies."
Ewald started a journal. You remember, there was a journal called the ZEITSCHRIFT FUR CRYSTALLOGRAPHIE.
Yes, published in the thirties.
That went dead with the end of the war. And Ewald, who was in this country, decided there should be a new journal, and started CRYSTALLOGRAPHICA ACTA. Either English or American, I forget which. But then the ZEITSCHRIFT FUR CRYSTALLOGRAPHIE got brought back to life, and I think they both exist. I remember publishing a paper in that on the Kirkendall effect and things like that.
I think we discussed this SCIENTIFIC AMERICAN article when we were discussing radiation.
Yes, and also, when we chatted with Wigner. It doesn't go much beyond the PHYSICS TODAY article, in history anyway, although there's more explanation. And there's a scientific paper later on, on this subject, in 1962. Just one question I had, the work that was done in this area during the war used neutrons, but I noticed that later work by Kaler and others used electrons and perhaps other particles as well. Did that all come from the war work?
Yes, it was stimulated by the war work. Initially we were interested in the effects of neutrons and fission fragments. The fission fragments really cause a great deal of damage in the fuel elements, because they have a lot of energy and they plow through and tear up the place. Someone pointed out in the postwar period that the fast electron had just enough momentum to knock a nucleus out, so you could get very sensitive forms of damage, much more sensitive refined effects. And that then became a major field. I must confess, I forget who did that work, but Kaler will know.
I'm just wondering whether there's anything special to say about some of these other papers that I have here, one "Intersections in the Silver Halides," with F.C. Brown. This is the same Brown who is now in our department? Seitz; Yes.
This is also a Tokyo symposium. Seitz; Fred and I met at a meeting of the Physical Society in Rochester, or some meeting in Rochester, and he was deeply interested in the silver halides and came to Illinois.
And has continued to work in this area.
Yes. He got interested in the use of betatron radiation in exploring the optical spectra of solids.
Was that a large field or was that something very special?
No, it's a very important field now. You can get continuous ultraviolet spectrum way down into the X-ray region, and there are a number of people who do this kind of work. Fred used a synchrotron that was up at the University of Wisconsin, I think since has been closed down. Actually took a job at Xerox in Palo Alto for a while. It was thought that he could get cooperation with people at Stanford, but it never worked out well. And he came back to Urbana.
This is another review which I suppose is also a symposium talk in Nuovo Cimento, on point imperfections in solids.
Yes. I think so.
It goes over some of the material, Lyddiard I see is mentioned here. Now we're going into. . . I'm going to turn this material over to Spencer, material that has to do with government and so on. "The Inter-relation of Ceramics, Metallurgy, Chemistry and Physics" is another general talk — it must have been a talk somewhere.
A talk I gave, yes, at some Metallurgical Society — what year was that?
It's published in 1963. But it doesn't say here. Actually the paper was presented by Mauer it says, but it doesn't say where it was presented. So that will become clear later on.
It might have been a symposium in Norway or something. forget — which Bob went to, and I didn't.
Right, and then here in 1962 finally is this REVIEWS OF MODERN PHYSICS article on effects of irradiation on metals, and that's comprehensive.
By that time, we began to understand what was going on in the metals. I didn't realize I'd published anything that late.
That was just before I went to the Academy, and I must have pulled a lot of stuff together that I hadn't been able to when I was working with NATO.
By this time, you're now involved deeply with government work, committees and work in the institutional side of physics, but solid state physics has also by this time changed character. I think it would be very helpful to close this part of the interview with some comments on the way the field looked mid-to-late-fifties. It certainly looks as though it's coming apart.
Yes, it exploded into many sub-fields, which happens to fields if they are important. People become very specialized, special techniques, special interests. In addition, of course, the whole business of cooperative phenomena took off. The first inklings were Dave Pines' work on the collective models.
How important was that work on the field as a whole?
Well, it gave one a grip on a new approach. And, of course, John was working away trying to get a better understanding of the cooperative phenomena, in order to try to understand superconductivity. I'm sure he's given you a good picture?
We haven't done that yet. No. We discussed it casually, but not yet in the kind of detail which is necessary to do it. So, fifties is a time when the field is changing character, because theorists are different now in the fifties, some of the theorists. They're coming in with techniques of quantum field theory.
And applying that to solids, and also with a different concept, the cooperative concept.
The oscillations. And so on.
That became an entirely new level. But before that, there had been the development of levels, you know, the sort of thing Cotell was doing, using resonance phenomena to get details of knowledge of what electrons were doing in solids. That in itself, starting in the forties, branched out into a very major field of its own. One could get information which was otherwise very difficult to get.
Yes, resonance techniques, both electron and nuclear resonance.
Who besides Cotell would be good to discuss this with?
Well, Charlie Shlicter worked in that area, and then there were a number of people. One of the individuals who I think followed it in great detail was Herring, but Cotell would be good.
Are there other important ways in which the field changed character in the mid-fifties?
Well, in addition, of course, it attracted graduate students in vast numbers, so that you built up a very large population.
There was a surge at around that time?
Yes. When we formed the division of solid state physics, I guess 1946 or so, just after the war.
— there were probably 30 people who were active in the field in this country, in a real sense. And ten years later . .
. . . some statistics on solid state that I need to get my hands on. On the way in which the field changed.
The jumps, yes, how many people were working, and perhaps even what areas they were working on. I think that will be useful to study, and perhaps include. So there was a change in the number of people, the kinds of work they were doing, and the degree of specialization.
Yes. Well, it was a good field for theses. Another thing that happened is that the whole field of physical chemistry, which had been a very important field when I was a student, somehow got absorbed into solid state physics or condensed matter physics. The kinds of individuals who once would have gone into physical chemistry chose physics.
At what point would you say that the materials side became incorporated into solid state physics?
Well, there was always some of that from the beginning. Individuals like Mott and so forth were interested in the properties of materials, the plastic properties of all these things, the things I try to tie together in that 1950 paper on imperfections. Another generation came along, which, because of the tools they had, lost interest in materials in general. Cotell for example. They could do things with pure materials and with very delicate equipment. So there was both a fusion — the term material science became intellectually acceptable — and yet there were people who worked separately, but created whole areas that were very important. Then, in the late fifties, early sixties, the Department of Defense decided to create these Materials Science laboratories, which would stimulate interdisciplinary work.
And you were very active in getting one of these laboratories for the University of Illinois.
Which of course is still flourishing.
We were helped, unlike the others, by the Atomic Energy Commission.
Well, they had people who just felt that they didn't want to be out of the action, that they ought to be involved too. Don Stevens, in particular, was sympathetic to it.
And was there a close interaction between the Materials Research Laboratory and the physics department right from the beginning, or was it set up as something separate?
No, there was a close interaction. For one thing, it gave the people in physics opportunities to do special things. Kaler, for example, could get an electron accelerator. Bob Mower set up a number of laboratories there, eventually became head of it.
Yes. That was another development.
Wheeler Loomis was involved in the planning of the building. He had retired in 1957, I guess, or '58, that period. But he took on the job of designing the building. Hoddeson; Did having this operation established and ongoing at the University of Illinois aid in keeping up the level of funding? Seitz; Yes.
During the more difficult periods later on?
That's right. We have gone through several periods in which funding has got very lean. There was one in the late fifties. And the establishment of these laboratories was one way of countering disaster. Of course then, another lean one set in toward the end of the sixties, and, in a sense, the physical sciences have never quite recovered from that.
From that one. Yes. They couldn't just cut off this laboratory, because it's a whole building, and the Materials Science Lab, though I can imagine them cutting off some other things.
Well, there were two kinds of laboratories, those funded by the Department of Defense, which we didn't have. They belonged to the university, period, and it wasn't required that the Department of Defense continue funding them indefinitely. As a matter of fact, they eventually turned them over to the National Science Foundation. Ours was done in an unusual way, handled in an unusual way. The Atomic Energy Commission, as I recall, in effect leased a plot of ground and put up a building, and then the university bought it back over ten years.
Of course those ten years have long since passed. I was involved in doing it, but I've forgotten some of the legal aspects. The university had to pay in some way to regain control. But that would have all been settled by the mid-seventies at the latest. I think the university paid out of the overhead, or some such thing — not important for this.
Well, I guess we've come to a good stopping point now. Thanks very much.
 Cyrus Eaton.