Bertram Batlogg

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ORAL HISTORIES

Photo courtesy of Bertram Batlogg

Interviewed by

David Zierler

Interview date

May 14, 2021

Location

Video conference

See catalog record for this interview.

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Interview of Bertram Batlogg by David Zierler on May 14, 2021,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
www.aip.org/history-programs/niels-bohr-library/oral-histories/46801

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Abstract

Interview with Bertram Batlogg, Professor Emeritus at ETH Zurich. Batlogg surveys his current interests in topological superconductivity and superconductivity in twisted layer graphene, and he connects this current research with his own work at Bell Labs earlier in his career. He considers the current state of play in high-Tc research and he recounts his family's Austrian heritage and his upbringing early interests in physics. Batlogg describes his undergraduate experience at ETH Zurich and his reasons for remaining to complete his PhD thesis work. He describes Bell Labs as the Mecca for his research as a postdoctoral fellow and then as a staff scientist. Batlogg discusses his work on Hall effect measurements, superconductivity, and heavy Fermions, and he describes his tenure as head of the solid state physics and materials research division. He describes the culture of basic science and how it changed from the 1980s to the 1990s, and he discusses his formative collaborations with Bob Cava and 1-2-3 YBCO. He narrates the story of meeting Jan Hendrik Schön and the issues that would lead to the investigation led by Mac Beasley. Batlogg conveys the scientific and emotional turmoil of this episode and the impact this episode had on his sense of trust in people. He describes participating in the investigation after he had already left Bell Labs to return to ETH Zurich to build up a research group with a focus that included topics such as charge dynamics and heavy Fermions in very high magnetic fields. At the end of the interview, Batlogg emphasizes advances in data acquisition and spectroscopy that propelled the field forward over his career, and he considers how some his research can contribute in the future to discoveries in both the applied and basic realms of science.

Well, these are old stories. At the very beginning, everybody was excited about just the high temperature itself, the scale itself. Very rapidly on, very early on, and it was partly work with Thom Palstra at Bell Labs, when we realized that the dissipative vortex motion in these materials is an issue. It means that in a high magnetic field the electrical conductivity of the superconductor is not better than that of a copper wire. It strongly depends on the orientation of the field with respect to the crystal. This disillusionment came quite early on, realizing that these superconductors are essentially two-dimensional, depending on the details of the materials. So it was clear that one would have to choose particular compounds where this anisotropy was the least impediment.

The bismuth copper oxides therefore were not high on the list of candidates. YBCO or the Y123 compound, however, was more promising. And so it depends what kind of application we were thinking about. Cables or electronic components. We had been working at Bell Labs in collaboration with Lincoln Labs and other institutions in the Consortium for Superconducting Electronics —we had been exploring, among other things, the use of thin film superconductors for microwave filters. That actually turned out to be a valuable application for cellular telephone networks.

At the end, I think it was the cost factor that made it not a big commercial success. Technically, however, it was perfectly fine, meaning the superconducting microwave filters, particularly for wireless communication. They have the advantage that the flanks of the band pass filter are much steeper than in traditional filters. Therefore, one can use the allocated frequency band more effectively, more information can be transmitted. And we demonstrated that, and actually that worked out very well. So this application in the form of a thin film on a substrate worked out very well. It did not make it to the market in large scale. There are some applications, as I understand, but not in large scale, because of the cost associated with that. So that’s one side.

The other side of making wires is an entirely more challenging enterprise, because one has to have large quantities, properly oriented grains, not breaking apart. One has the problem of grain boundaries not being very good junctions between grains, and so on. Companies had been working for long, long while. Several demonstration projects had been made in various places in the world. After a successful 1 km demo project in Essen, Germany, a 12 km application is being planned for Munich. In addition, research magnets involving cuprate superconductors are also being produced. Applications in wind turbines are also explored, mainly as a mean to reduce weight. As the emphasis on energy saving becomes more pronounced, we might see more applications of superconductors.

Zierler:

Bertram, let’s take it all the way back to the beginning. Let’s start first with your parents. Tell me about them and where they're from.

Batlogg:

Well, my parents are both from Austria, from the westernmost part of Austria, a small state named Vorarlberg. Mom and dad lived in this mountainous area. My dad was one of five children. His father was a small farmer who also worked in a local hydroelectric power plant to earn some money. And he was, smile or not, he was mayor of the small village with about 150 people living there. There was no income associated with that; it was just fame, in quotes, and it was service to the community. We three children also grew up there. The village is known to be well protected from the sun. [laugh] It is on the wrong side of the valley and does not get much sunshine because it’s too close to the steep mountain cliffs.

Zierler:

[laugh] What languages were spoken in this village?

Batlogg:

It is the local German, which is a language close to the language spoken in the southern part of Germany, and also in nearby Switzerland. It is distinctly different, language-wise, from languages and dialects spoken in the rest of Austria. This part of Austria is very small, about 2,600 square kilometers, with about 400,000 people living there now. And they are also geographically sort of separated from the rest of Austria by a high mountain ridge, always oriented towards Switzerland and Germany.

The languages are very interesting. I'm interested about those things, because in those days, before the mobility of people was not as high as it is today, we could spot people—we could locate people by the details of the language, down to about two or three miles. People in the same valley, two miles further up, spoke a slightly different dialect. You could hear them. And I found it just amazing how languages had developed over the centuries so they could be distinct on the level that one can hear the differences so easily. Not just the vocabulary; that was one part. But also the way of pronunciation. It’s a very strong accent, which I could never get rid of.

And then you asked about parents, yes. Let me just tell you more about them. My father was a mechanical engineer, and he had for all his life worked at the same textile manufacturing company. This company employed about 2,000 people in a little town of about 10,000 people. So it was by far the dominant employer, and I'll come back to that in a second. He was very much also a hands-on person, in addition to a designer. Fire prevention is of utmost importance in a textile factory, because of all the dust that’s around, he also was the chief of the fire department in that factory for more than 40 years. And he also was, on the side, the chief of all factory fire brigades in the state. All was volunteer work. Dad was on the road in the evenings, on the weekends, always in his fire fighter uniform, having some official function here and there. He had lots of gold on his shoulders and medals of recognition on the uniform. Our dad was a dedicated volunteer man.

Zierler:

Did your mother work outside the home?

Batlogg:

Yes, she did. Mom worked in an administrative function outside the home. But then when the three of us joined the family, she stayed at home, was a wonderful housewife, a dedicated mother. She put lunch on the table at a quarter past twelve, because that’s when we came back from school every day. Our father also came for lunch, by bicycle. So it was a very traditional family life.

I think because both of my parents had to serve in World War II and had seen the horrors – they wanted us to grow up differently. They wanted us to believe in the goodness of people, to respect people, and to trust them. And that was the basic philosophy in our family—unspoken, but it was just the way they tried to raise us three children, in a protected, in a loving environment. Because when they were young people, they had seen the worst of mankind. I think my two sisters and I still carry this basic positive and optimistic attitude in us, in our lives. And our parents have passed on long time ago, but that’s what they have left us.

Yes, they did know that. I think that they were not aware probably of all the details that we know nowadays. And they had seen what happened to transportation of Jewish people to the concentration camps and so on. I think this was all part of their horrible experiences they had to go through as young people.

Zierler:

Bertram, as a young boy, born five years after the war, do you have any early memories of the devastation of the war? Or where you grew up was not that badly harmed?

Batlogg:

Oh, sure, I do have memories, because Austria was occupied for ten years, until 1955, by the four victorious powers—Soviet Union, America, France, and Britain. Austria was divided up in four sectors, and our region was occupied by French troops. Almost every day I saw the French troops walking by in front of our house.

From then on, I went to what’s called the gymnasium. It’s similar to a high school, except it’s organized differently. Our class was very small, some 25 students only. Fourteen girls, eleven boys. We had a wonderful class life, and we stayed together all the years. Just recently we celebrated our 50th graduation anniversary. We were just as happy together as we were 50 years ago. Several of the teachers, including in physics and in chemistry, were excellent.

Perhaps I should tell you a story about the physics teacher. There were no advanced courses, just one type of course. And we only had two lessons of chemistry and two of physics per week. Learning was intense. The first physics teacher was a senior person, close to retirement. And he adopted me as his teaching assistant, something which is unusual in high school, of course. But I was allowed to come in the day before lectures and help him set up the demonstration experiments that he would show us the next day. This way I learned a lot about physics and how to do physics, literally behind the scenes.

And then in the last two years, a freshly graduated young man came, very nice, dynamic and energetic. Gerhard Blaickner quickly became our favorite teacher. And he also adopted me as his physics TA. One afternoon I realized that experience and craftsmanship make a difference. The teacher and I were trying to set up an experiment—it was a simple electronic circuit. But the oscilloscope didn’t show what was expected. The signal was jumping around, it was noisy, garbage. Yet we were sure we were following the instructions. After an hour or two of us fiddling around the old teacher walked by, realized that we had problems, and he said, “Oh, you guys, all you have to do is just—you put a high impedance resistor across the oscilloscope input.” Which we did, and lo and behold, we had the cleanest signal that we could ask for.

The bottom line of the story is, the old man knew that in reality you have to deal with noise. And so at that point, I realized that real-life experience also makes a big difference, not just knowing the theoretical details. It was a good lesson learned there.

Blaickner was a good teacher, and at the final formal exam, I remember he asked me about the basic theory on electrons in an atom. This was quite an advanced topic for high school. And the examination team—including also several external teachers—was quite impressed when I explained the spectral lines series in the hydrogen atom. And I still remember the Lyman, Balmer, Paschen Brackett, and Pfund series—one over n squared minus one over n two squares. And so I was off to a good start into physics.

While that was it in terms of the formal education, I think what formed me much more was what I did on the side. The grades were good, decent, but I didn't care too much about the school, about Latin, and other languages. We had an outstanding philosophy, German and history teacher who had a big influence on our class. But I learned most of the physics and chemistry stuff outside school, at home with my hobbies. If you are interested, I'll tell you those stories.

Zierler:

You mean hobbies including physics?

Batlogg:

Yes.

Zierler:

Please!

Batlogg:

What was the environment that led me to do physics? In our basement, our father had a wonderful work room with lots of tools. Many afternoons I spent there. As a small boy I got an electric model railroad kit for Christmas. While I liked it a lot, its lasting impact was that I could use the transformer and the power supply for all kinds of electrical experiments. Among other things, I was doing electrolysis of water, producing hydrogen and oxygen out of water. And you know what you do with that, of course—you let them explosively react afterwards. So it was really always fun to do things.

Originally, I meant to go to University of Vienna or to University of Graz, which are both good universities. So my mind was set. Then in between came this one important year with consequential decisions. In Austria we had compulsory military service, so for one year, I was off any academic activities.

And two things happened in that year that brought me to ETH. The first one was at the military service, where I was with the high-mountain troops. The field exercises were quite harsh. In one particularly grueling exercise, we were snowed in for a few days in these small snow caverns that we had dug out. Supply lines collapsed, essentially, we barely had enough food. We did survive, with some frozen toes. But we didn't get enough to drink for quite a few days as we had to melt the snow ourselves, which is a pain in the neck to do. And that hurt my kidneys.

Back in the barracks, I had enormous pains and the military doctor very badly misdiagnosed the cause. On the weekend I went to the private doctor at home, and he diagnosed right away a serious kidney stone as the reason for the pain. You might have heard about renal colics. Our mom told us that renal colics are more painful than giving birth, and she knew what she was talking about.

So the doctor did not allow me to go back to the military, I had to stay home for about three weeks, drinking lots and lots and lots and lots of a particular tea, until the stone had passed, which was wonderful. But in these three weeks, I had all the time at my hand, and could meet with this particular nice young girl whom I had known from mountaineering the years before. We became good friends, and half a century later we are still a happy couple. The incompetence and missing mastery of his craft by the military doctor had a very positive consequence in this case.

The second decisive event was that a friend of mine, one year senior, had started his engineering studies at ETH Zürich, and he told me how much he liked ETH. Zürich is only about 100 miles from home, while Vienna is some 400 miles away. ETH had already a very good reputation at that time, and by now it is one of the highest ranked—I think it is the highest ranked university on mainland Europe.

Well, in the first semester, we only had mathematics, no physics at all. Then came introductory physics taught by Werner Känzig, who was a fantastic teacher. He handed out a wonderful handwritten manuscript that he reiterated every year, literally cut and paste at that time, by hand. And he was an enthusiastic and very energetic person. We liked him, and he made a big, big difference.

He was an efficiency-oriented person. Actually, he came from General Electric Research in Schenectady, New York, where he had spent some years and then came back to ETH. So he had experienced professional life in a different place and different, efficient corporate culture. He didn't like administrative nonsense. When he passed away, a rubber stamp was found in his desk drawer that said “Professor Känzig has no time to fill out questionnaires.”

Zierler:

[laugh]

Batlogg:

Very often later in my life I wished I had a stamp like this.

Zierler:

[laugh] That’s great! Bertram, what exposure did you have to laboratories and experiments as an undergraduate?

Batlogg:

Batlogg:

Well, the system was different. It has only slightly changed now. We had what is called diploma track studies. Usually after four and a half, five years, you would end with a diploma. And then later on a few students continued with the doctoral studies, almost exclusively at ETH. While working towards the doctoral degree, we were not students in the usual sense, with classes and exams, no, we were scientific collaborators, because we were part of a research group, of our choice. And we were for at least one day per week involved in teaching. What were at that time diploma studies later on were reorganized into Bachelor and Master programs, following the Anglo-Saxon scheme.

So, was it usual to go on? No, not too many students in physics stayed on to do a doctorate. More so in chemistry. And almost none in mechanical engineering. A doctoral degree in engineering was not very popular. Wasn’t necessary, because an engineer has to get stuff done, has to know how to do things. In physics, it’s somewhat different. So I did stay on, and I had a hell of a good time, as a doctoral student. I got all the freedom and support.

At the very same time, just about a year or so before I started my diploma thesis, an important paper came out of Bell Labs by A. Jayaraman, Ernst Bucher and colleagues. Both became good friends, later, and I’m still in contact with them now. They reported the discovery of a pressure-induced semiconductor - to - metal transition in Samarium sulfide, SmS. A landmark discovery. The necessary pressure is quite modest, six and a half kilobars. You can produce it just by using the tip of a needle to scratch the surface of the SmS crystal. The scratching permanently transforms the black crystal to a metallic golden trace. It’s a spectacular experiment to do.

For my master’s thesis, my task was to figure out the mechanism, and what drives it. I figured it out pretty well, and I published a paper in Physics Letters. Physics Letters had the high reputation then, because important papers were published there by high-energy physicists, and also by e.g., Brian Josephson. Anyway, I published this paper and then continued to work on intermediate valence 4f compounds. Because this golden high pressure SmS is not the usual metal. Samarium is in a mixed-valent state. The electronic configuration of Samarium is a quantum mechanical superposition of divalent 4f6 and trivalent 4f5-5d1. The one electron in the d state forms the delocalized metallic state. Nowadays, one would call it a novel quantum material. We just knew it was a quantum mechanical mixture. That was in some sense the main direction of my research. There were several other related and interesting compounds later on in my doctoral thesis.

But the one point I want to mention is that systematically reading the literature stimulated many new ideas. I knew what the colleagues at Bell Labs were working on at that time. Bell Labs, —this special place, we only knew from papers. And we also knew what colleagues at IBM Yorktown Heights were doing in this field. During my doctoral thesis I had essentially two big competitor groups at those places.

I think I did reasonably well in the competition, and by the end of my PhD, I had published, I guess, more than a dozen papers, including one PRL where, together with my colleague Hans Ott, we had confirmed in Thulium selenide TmSe one of the predictions that Chandra Varma at Bell Labs had made. And no wonder I had an opportunity later on to join either one of the groups, from being a competitor to being a collaborator.

Zierler:

I'll direct my broad question earlier specific to this point in your career, when you're really starting to develop your professional identity, and that is the interplay between theory and experiment on this research that you were involved with right at the moment between graduate school and your professional career.

Batlogg:

Well, it was not textbook stuff.

Zierler:

Because it was all new, you mean?

Batlogg:

It was new. It was at the forefront of what was going on, in the best of minds in the world. And we were at this remote place, somewhere in Europe, in Zurich. But the driving forces were in the United States, in the two laboratories mentioned before, I was closely watching what was going on there. Typical for the generous support I enjoyed—I think it was in the second year of my doctoral thesis—Peter Wachter sent me to a magnetism conference in Toronto to present a paper. As a young kid, well before the doctoral thesis was done. And at that occasion, I also traveled to Murray Hill to meet these famous people that I had only known from papers. And I got to know them all. And from then on, I could connect faces to all the theories and experimental results that came from Murray Hill.

Perhaps I could have gone to Saclay. I don’t know! No, there’s a big difference—if you come to the United States with an accent, which I never could get rid of, and you speak decent English, people are so friendly and say, “Oh, I like your accent. It’s so cute.” That’s our experience in the United States. If you go to France with a school French, which was pretty good, but of course not with a polished pronunciation, I always felt as a stranger. The attitude towards a foreign person speaking your language in France is different from what it is in the United States. It’s just a cultural observation that we have made, which made us, my wife and me, feel very welcome in the United States. Because people were taking us just the way we were.

What was your next project? What did you take on next at Bell?

Batlogg:

Oh, gosh. I always had many things going on at the same time, including superconductivity, heavy Fermions, and a few other topics. I remember [laugh] cuprous chloride, CuCl - because it got me into superconductivity. A paper in a Russian journal reported that if you squeeze on CuCl and cool it down, you would see resistance drops and jumps that were indicative of superconductivity at enormously high temperatures. And a colleague in the United States also reported having observed resistance drops. Speculations about excitonic superconductivity started. And I thought, this is just crazy. Cuprous chloride, as I remembered, is just a transparent insulator.

And so I got together with Joe Remaika in our department. You might have heard Joe’s name before, from Zachary Fisk. Joe was a self-taught amazingly creative wonderful person, growing crystals of all kind, and a good friend and mentor who passed on way too young. “Joe, can you make cuprous chloride, CuCl?” I asked. And he came up with a fantastically simple and efficient method to make the world’s best CuCl crystals. So I got these large, centimeter size crystals, which I had to cut because they did not fit in the equipment. I did various kinds of high pressure experiments on them, and there was no trace whatsoever of superconductivity there.

What I did find out is that under pressure, cuprous chloride could break up into CuCl2 and copper. Copper was segregating into metallic filaments, perhaps, and these filaments probably were the reason why the resistance drops had been seen before. High pressure induces crystallographic phase transitions, and I also found ionic conductivity, but all of this was just a sideshow. Cuprous chloride is no superconductor whatsoever.

To complete the story with an anecdote. At the March meeting, the speaker before me warned, “Oh, one has to be so careful about this cuprous chloride. It is hydroscopic, and you have to treat it carefully.” When my time came, I reached into the pocket and put this centimeter-sized piece of colorless cuprous chloride with bare fingers on the overhead projector, and said, “Cuprous chloride is not air sensitive at all, and it is very stable.” That was the end of the discussion, actually. [laughs] Joe’s expert craftsmanship was essential for solving the puzzle. This was the only Physical Review Letters that I remember reporting a negative result.

Zierler:

What’s the significance of that?

Batlogg:

Cuprous chloride does not host excitonic superconductivity, was the message to the community. For me personally it was the first encounter with unconventional “superconductivity”, even in a non-superconductor. Then I started a few other projects, including, the pressure-induced compressibility collapse transition in ReO3, and heavy Fermion magnetism and superconductivity, mainly with Zachary, Jim Smith and Ernst Bucher as crystal growers, and local collaboration with Davis Bishop and Brage Golding. Quite helpful for my later science was work, again with Joe, on barium lead bismuth oxide, Ba(Pb.Bi)O3 , that Art Sleight had found in 1975 to be superconducting at around 12-13 Kelvin. The novelty was oxide superconductivity with a Tc above ten degrees, and it gave me quite a head start.

This goal to manipulate the background and the ingredients in a favorable way, I think we both had in common. He knew how to make the compounds very well, and to analyze the structure quickly. And I brought to the table how to measure it, how to make sure we knew what we had in terms of physical properties. So it was a collaboration on the same level, towards the same goal, but we had different parts of the task separated for us.

Zierler:

What were some of your main findings in your research with Bob? What was so significant?

Batlogg:

The identification of single-phase yttrium barium copper oxide 1-2-3 YBCO, with superconductivity at 90 degrees, was a big hit. We wrote a paper and also reported first electronic properties, such as critical fields, temperature dependent resistivity, and the unusually low density of electronic states at the Fermi level. Before that was first La,Sr cuprate with Tc near forty K . But in terms of finding new compounds, we discovered several more superconductors together.

YBCO of course put us on the map. Very clearly. At the famous “Woodstock of Physics” March meeting in 1987 I presented all our work, and that of our Bell Labs collaborators as well. The single phase YBCO work and the following subsequent work, were the most important parts of our contributions at the very beginning. Later on, (Ba,K)BiO3, a non-copper oxide superconductor at 30 K, and several more studies of new compounds we did together. But there are so many papers, I don’t want to go through them in detail.

A few months after the YBCO single phase identification and physical measurements that were clearly hinting at non-phonon mediated superconductivity, new surprising insights developed. We were among the first to systematically vary the electron count by varying the La/Sr ratio or the oxygen content in YBCO. A general phase diagram emerged and over the years we explored it in more detail together with Art Ramirez, Hide Takagi and Harold Hwang. Identifying these phases involving spin and charge degrees of freedom became for decades a central theme in this research field worldwide.

Let me mention something about this YBCO 123 identification. Bob had told you before that we did it within a few days. It was a day and night work, and we had it, I think, on the third of March 1987. We sat together with the patent lawyer George Indig to write a patent. Now, this is yet another example that I would like to bring up, of incredible unique level of craftsmanship on the lawyer’s part. I hope I don’t abuse the word “craftsmanship” too often, but it is craftsmanship on the level that was unheard of.

So we had told George that we would come the next day with what we had found, and we would bring some data and so on. Now, imagine the following. Bruce van Dover, the other collaborator, Bob and I—came early in the morning, gave George some background information, what we had done, showed our data, and so on. In between we went back to the labs, got the latest data to make sure that we had everything together. And George would sit with his legs on the table, with secretaries on the left and on the right hand taking notes, and he would dictate the patent word for word. Barely a correction was necessary. And every 15 minutes, the two ladies would change, go back and type up what he had been dictating.

Because, as you can imagine, a patent is a very well-organized piece of document in lawyer-language, George had pre-structured it fully in his mind. It’s a different way of communication, not a scientific publication. It was foreign to us. And George did it the whole day long, taking our latest results and figures into consideration. The graphs that went into the patent, we gave to the drafts people during the day. And in the evening—I think it was around 8:00 or 9:00, the patent was completed, typed up, with all the graphs. The same day! In all the coming years, this document and its content had withstood the harshest of interrogation and cross-examinations. And why it then took more than 16 years, allegedly the longest ever, for the patent to be granted in 2003, is known to a few people only. A story to be told separately.

An absolute key patent was produced in one day. And it was sent off with a courier to New York in the evening, and that was it. We went to write our paper the same night, the Phys Rev Letter, with more recent data measured during the day, and it was done in the morning. So this PRL was written in one night as well!

Zierler:

[laugh]

How should I put it? The misconduct happened independent of who the coauthors were. There were some 20 people who were coauthors. I was one of the better-known coauthors, but there were many—and there were numerous papers that I was not involved at all. Misconduct happened independent of the place where the various pieces of the experiments had been made. So some of the studies were done back in Konstanz, others at Murray Hill, in various labs. And also the misconduct was independent of who was department head or manager of the group. It was just not related to any of those factors.

And so when this came to light, the science community rightly was upset. All the coauthors were shocked. And I was more than shocked. I was shaken in my foundation as a person, as a human being, and I was shaken as a scientist. This was a traumatic experience for me, and I think I only made it through due to the help and support that I got from so many directions, including family and also friends in the physics community. It still works in me very frequently, actually. I had all this trust in a young person.

Perhaps all of the above. However, I think being misled by someone who you trust was the most hurt. In addition, of course, the fact of observing the many reactions of the community with both polarities. I was surprised about some comments by colleagues that I thought would be more thoughtful in terms of first looking at the facts and then talking. Many people knew ahead of everything what was wrong. They were just so smart. And they were just wrong, as well. But that was hurtful as well. So there are many feelings that go with that, and still go with that. It’s not over yet. Perhaps I won’t enjoy dinner tonight, as a result of that. I hope not. But it’s something that shook me in my foundations. And, well, I don’t wish that anyone has to go through that, ever again. In addition to external reactions, a nagging concern was and still is, that I had presented some of the later discredited results in my own talks.

One can see something positive in that experience. I think we all have learned something from this disaster. As a community, we learned what can go wrong. And what has happened in the last 20 years in numerous other cases, was not much different. What we have learned is that being very critical, perhaps even a bit suspicious, appears to be necessary occasionally. That’s obvious.

As a result, a few years later ETH, I got involved in teaching two courses about scientific misconduct, together with a colleague who was doing science theory and philosophy. There was nobody who could talk more authentically about scientific misconduct, obviously. Students were very much appreciative of those discussions. Of course, a little bit of drama is involved here and there if you go through all the famous cases of misconduct, not just the one that we talked before. There are many such cases, well documented. They all make good stories, particularly if the lecture is at 5 pm in the evening. But I got involved in trying to spread the firsthand experiences to students, and also to some faculty, actually. At the end something positive could be made out of it.

As you put it correctly, integrity was not a point to be discussed. I took it as, if anything, as a given. I might call it naïve now, but integrity was not something at your disposal. It was just part of being, part of doing a job. When my grandfather, Mom’s dad, built wooden homes—he was a carpenter – it would have never occurred to him to take a shortcut, because the house would fall down 20 years later, to make the point clear. As a student in gymnasium one summer I had been working in a bakery. Well, bakers as craftspeople also know that you do not take shortcuts. You don’t sell 0.95 pounds of bread as a one pounder. So my experience as a young man working at various jobs was that there is no such thing as a shortcut, if you master a craft and want to be valued member of society. It has to be right and correct and trustworthy.

Just to repeat: I had started at ETH well before that. Well, let’s put it this way: I like to be with young, bright people, and they know and they feel that I like to be with them as well. So, my goal was, explicitly or implicitly, to continue to do excellent science, with PhD students and undergraduate students, as you would call them. To be a good tutor on that level, and also to be involved in the broader aspect of teaching at the university. So there were quite a few aspects.

The first task of course, in terms of research, was to build up a laboratory, several laboratories. Infrastructure for crystal growth and sample preparation in general, including high vacuum thin film deposition. Infrastructure to do measurements and so on. So there were lots and lots of things to be organized so we could do measurements at the end, do some science with it. And the other one is getting involved in teaching, and in the broader aspect of teaching. One part of my activities were taking care or nurturing a research group with young talents, and the other one was being involved in the ETH-wide level of promoting good practices in teaching as well.

Within the Physics Department, later on I took on the responsibility as the director of studies, which is next to the department head function the most important job, in particular for the students’ education. So I was in charge of all of teaching activities.

To first start with our own group. I was fortunate enough to be able to hire a superb technician, Kurt Mattenberger, a friend of mine from my own student days. He was a technician then, and he remained the most fantastic gifted, universal, everything-knowing technician that one can ask for. Kurt was better than most doctoral/PhD students, by the way. Kurt would grow crystals during the week, and on the weekend could run the combine for harvesting grain for his farmer neighbor. He also managed many PhD students’ work very well. This was the first important thing I could do, is to hire Kurt.

Then I hired Janusz Karpinski and his two or three colleagues for materials synthesis. He’s an expert in high pressure, high temperature material synthesis, produces all these unconventional superconductors and other compounds of interest, such as MgB2 and inter-metallics. This way we could start right away with doctoral/ PhD students studying organic materials and superconductors.

The rather fast start was possible because I had been preparing it well before I fully came to Zürich in September 2000. So, yes, I moved into a freshly furnished office and the laboratories were also functioning, at least partly. Purchase orders had been filled for equipment. And then several wonderful young talents joined us working towards their doctorate/PhD. And so we got many good things going, including having international colleagues visiting us.

Other components of group life? How should the group work on a social level? Doing the scientific part is something students will learn, and I can teach them a lot. In some sense that’s the time consuming, but easier part. An equally important aspect is to nurture a group life that is not focused on the professor, not focused on me, but is focused on their collaboration. Despite the fact that they all had to do work on their own doctoral thesis, students also have the joy of interacting with each other, learning from each other, benefitting from others’ expertise and experience. And that component was emphasized a lot. Internal seminars, short presentations, regular tea time are a way to foster those interactions. And having lunch together, prepared by one of the group members. A poster on the wall summarized it succinctly: “We work hard and play hard.”

Our students liked to be together. They did not feel they want to leave the place, knowing that harsher life is waiting for them in the new workplace. They had such a good life doing science and having good friends that sometimes I had to stimulate them to move on.

Zierler:

Was there a point when you got back to ETH, when something was fully accomplished, as a researcher, as a mentor? Healing is obviously a process that can never be completed, but was there a certain point where you felt you could move on with your life? That this was not central to the things you were thinking about?

Batlogg:

Yes, in the sense that at some point I realized—and it might sound strange—that my contributions to high temperature cuprate superconductivity were done. While I was much interested in observing what was going on, I also knew that the type of next questions that need to be answered or investigated are not what I want to do, or that I had the capability to do. Put it in a general way, I rather like to work on the first chapter than on the last chapter of a book.

But this is a personal preference. Highly respected colleagues get enormous satisfaction out of dotting the i’s and crossing the t’s, and then the chapter is closed for everyone. So I think it is just a preference of what people think is more suitable for them. I thought new things would be fascinating for me.

Zierler:

Like what? What else was new at this point? High-Tc is in the rearview mirror. What’s the frontier for you?

Batlogg:

The frontier became multifaceted: charge dynamics, Seebeck effect and optimal device performance in organic molecular crystals; new superconductors, including MgB2, osmates and the Fe-based family; heavy Fermions in very high magnetic fields, Co-perovskites with charge ordering and magnetism, and other topics were high on the list at ETH.

One more frontier: in terms of a new experimental approach, we have systematically developed and demonstrated the immense power of microstructuring and contacting samples of all kind using a focused ion beam. This FIB technique has opened new frontiers in the study of superconductors and all kinds of correlated electron systems, and also other types of materials. FIB microstructuring has become a much-appreciated way to study emerging electronic phases in quantum materials, to use contemporary language. A lasting contribution, it appears.

Here is another aspect about frontiers in physics: While I was director of studies for some six years, I had the pleasure to chair some 250 PhD defenses in physics. At that occasion it became clear how enormously rich physics is, in the broadest sense, and also which particular important role condensed matter physics has to play in the interaction of physics with society in general, in bringing benefits to everyday life. I think it will have a strong base in creatively making new materials, and tweak them to do what fascinates us intellectually, and also leads to useful applications. In the long run, usefulness is welcome. In that sense we also do have some responsibility to cultivate the connection to society. Yes, it is fascinating to investigate and talk about black holes, dark matter and dark energy. That’s wonderful. I think bringing the benefits of physics also to the daily life is just equally important.

Zierler:

To state the obvious, all applications must be born in basic science. It is the prerequisite.

Batlogg:

Let me expand your statement, which I fully agree with. Our director, Bob Laudise, the person I mentioned before, used to say, “Everything has to be made out of something.”

Zierler:

I love it. [laugh] Including the universe! [laugh]

Batlogg:

“Everything has to be made out of something.” And in a sense, he captures why, condensed matter physics and materials science are an integral part of the human endeavor. Of course, there are ups and downs, and there are more important seasons and less important seasons, there are springs and summers. In retrospect I was fortunate that my career coincided with springtime and summer, represented by high temperature superconductivity in general. And I wouldn't want to have missed it.

Talking about fortunate circumstances, I like to mention that I was privileged to meet numerous outstanding physicists. That made a big difference in teaching. When teaching advanced courses, in particular the popular Physics in the Smartphone course that I had developed, with student involvement, the students realized that I was not quoting a textbook. The students realized that I am first of all enthusiastic about physics, and I could capture that enthusiasm and carry it to them in the classroom. They appreciated my firsthand experience, not only with physics but also with the physicists behind it all. So combining physics aspects with physics people who made physics happen is one aspect that I found very, very beneficial in teaching classes.

Now a short anecdote about my involvement in teaching on a wider scale. Back in 2005 ETH was celebrating its 150th anniversary. A full day was dedicated to new ways of teaching, and I had worked on the organization for two years. Every professor and all students could participate, as all classes were canceled. One of the lasting impact was the introduction of the Golden Owl Award, to be given to the best teacher yearly in every department. The political landmine was that the Rector/vice president for teaching could not possibly made the selection, as the faculty would not go along. Therefore we invited the student organization to organize the survey. Ever since, the Golden Owl awards are presented every year at the Academic Day, the most prestigious ceremony at ETH Zurich. In this way the importance of good teaching is emphasized even at the high quality school as ETH is. At ETH, I was not doing only science with the people in my group, but also trying to influence the teaching on a much broader level in the department, and ETH wide.

Zierler:

Bertram, now that we've brought the conversation right up to mountain biking, for the last part of our talk I’d like to ask a few broadly retrospective questions about your career, and then we'll end looking to the future. So the first thing I’d like to discuss—we haven't really talked about it yet—and that is the theme of technology, and the way advances in technology have been most relevant for your research. And that’s broadly conceived. By technology we can consider instrumentation. We can consider computers. We can consider modes of communication and materials. What sticks out in your memory as most important in terms of technological advance?

Batlogg:

Well, there is a straight answer to that, and I start with data acquisition. When I came to Bell Labs, John Rowell and Bob Dynes plotted the tunneling spectra with a special X-Y recorder directly on paper and everything went from there. Perfect.

First, I introduced electronic data acquisition. In this way, I could do much more with the same information afterwards. First, I got myself a Hewlett Packard computer that had an HP-IB interface bus that has survived as IEEE interface. It could read out several multimeters at the same time. And later on, in order to do other experiments, I got myself a DEC PDP-11 classic mini-computer, with advanced data acquisition boards.

In terms of equipment, I had one of the very first commercially available Quantum Design SQUID magnetometers, with a single digit serial number. Later on I signed more than half dozen purchase orders for similar machines. This first SQUID magnetometer was ultimately essential for our work on superconductors, because magnetic measurements in low fields and on very small samples were possible. This way, I could trust the Meissner effect data quantitatively on samples with superconducting components, when we searched for new superconductors.

Spectroscopy is another example. While I had studied optical properties of solids in my doctoral work at ETH, at Bell Labs I set up a Raman spectroscopy lab for high pressure studies in diamond anvil cells. Structural phase transitions were the main topic. Many more advances in instrumentation came later on.

Zierler:

And why spectroscopy? Why do you single out spectroscopy of all the things you've worked on?

Batlogg:

So I would feel not very comfortable predicting in detail what will happen, and like to mention a little surprise. We have patents and publications on manganese oxides, colossal magnetoresistance materials, speculating that they might be used for memory devices or sensors. Who knows? Actually those papers—and that’s the surprise—on spin polarized inter-grain tunneling, and electron-lattice coupling, are even more frequently cited than our superconductor favorites. I don’t know why! It’s not predictable.

In the broader context, we think about organic semiconductors. Nowadays, we can buy gigantic flat panel TVs, displays, and they often involve OLEDs, organic light-emitting diodes. I don’t say that I contributed to a particular material there, but it is the type of basic understanding of what makes a material do certain things that ultimately will end up in an application. All that research is now being exploited on a huge scale, mainly by South Korean and Japanese companies, and others as well. I think there are only a few of manufacturing plants in the United States or in Europe applying this technology. However, I would guess that a large fraction of the underlying science of the OLED displays does come, and did come, from basic research done at universities and other places in Europe, in the United States, and other places in the world.

In general we cannot control where exactly our basic knowledge will diffuse to, and which company will translate it into an application. Within Bell Labs and the huge AT&T corporation that may have worked, say, 50 years ago. All activities, from research to manufacturing, were fully integrated and the company had all the time to wait until the engineers managed to translate new insights into technology. Nowadays, it’s a different style of translating research results into products.

And I wonder what will come out of all the research on quantum computing, for instance. I'm not an expert in that at all, but I wonder which company, at the end, will actually benefit most from all the great research at universities. Who will make the big money on it? But if we would stop thinking about new science based on which company might benefit from it, I think it would have a quite negative impact on our activities.

Zierler:

You mean those considerations cannot be baked into the discovery mode? That has to come after?

Batlogg:

I think so. I think it was always the question in the context of why AT&T would have Bell Laboratories that costs so much money. Well, we look back and see what came out of it. Not just the Nobel Prizes, but many, many new technologies. Not to mention all the highly trained and successful scientists in many fields who went to universities to educate the next generation. Thus, it is very difficult, if not impossible, to make the connection between somebody’s latest discovery and the potential future application that benefits society. The path is very diffuse, and it might be very long.

I'm only aware of a very few examples of rapid deployment, and the most prominent ones probably are the LEDs, the light emitting diodes, that have revolutionized illumination everywhere. The invention of the blue LED, honored with the Nobel Prize there, followed a clearly defined goal and purpose. The time between this invention and its application in everyday life around the world was incredibly short, and we all witnessed it. But I guess this is the exception.

Zierler:

Bertram, it has been a great pleasure spending this time with you. I am so glad we were able to do this. I'm so glad Alice White connected us. And I'm so happy that you were generously able to share all of your perspective and insight with me. Thank you so much.

Batlogg:

Thank you, David. It was my pleasure.