A New Look at Spin Transport: Spinning a Negative into a Strength
A New Look at Spin Transport: Spinning a Negative into a Strength lead image
One of the goals of spintronics is to find ways to use the spin of electrons to convey information, particularly in solid-state devices. A key challenge is that spin is not conserved in such devices, so the distance spin carriers can travel is limited. This distance can be extended with cryogenics, but this creates its own set of challenges.
Zucchetti et al. examine this problem from a new perspective by viewing this property of spin carriers as a strength, rather than a drawback. By employing directional electric fields, the researchers were able to extend or restrict the distance over which the electrons could transport spin.
“In our work we have demonstrated that the distance travelled by spins can be strongly increased or decreased by applying an electric field parallel or antiparallel to the spin diffusion path,” said author Carlo Zucchetti.
The researchers generated spin-polarized electrons in germanium. By default, these electrons can travel approximately 20 micrometers before they become depolarized. A 5-volt electric field applied in either a parallel or antiparallel direction doubled or halved that distance, respectively. The researchers’ ability to tune that distance enables them to electrically manipulate information encoded in a spin current.
Crucially, this process takes place entirely at room temperature, which avoids the need for complex cryogenics. As a result, the researchers anticipate several practical applications for their discovery, particularly in modulating this effect for use in next-generation devices.
“We are already investigating this point, and we have hints that such a spin modulation can be as fast as 10 GHz in realistic device configurations,” said Zucchetti. “We are just at the beginning.”
Source: “Electric field modulation of spin transport,” by Carlo Zucchetti, Adele Marchionni, Monica Bollani, Franco Ciccacci, Marco Finazzi, and Federico Bottegoni, APL Materials (2021). The article can be accessed at https://doi.org/10.1063/5.0073180 .
This paper is part of the Materials Challenges for Nonvolatile Memory Collection, learn more here .
