June 4, 2024
The University of Tokyo
Keio University
◆Highlights
Proposing a mechanism where atomic vibrations in chiral materials (materials with broken mirror symmetry) generate spin.
Spin can be injected into an adjacent metal simply by applying a temperature difference to a non-magnetic insulator.
Contributing to the realization of high-performance, low-power devices through the development of environmentally friendly spintronic devices that do not use heavy elements.
A research group led by Associate Professor Takeo Kato of the Institute for Solid State Physics at the University of Tokyo, Project Assistant Professor Takumi Funato (at the time of the research) of the Global Research Institute (Spintronics Research and Development Center) at Keio University, and Associate Professor Mamoru Matsuo of the Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, has developed a new theory that well explains recent experimental results in which flowing heat through a chiral crystal causes spin to flow into an adjacent metal. Focusing on the effect where local rotations of the crystal, caused by atomic vibrations in the material, align the spins of electrons in a specific direction, they have elucidated a new coupling mechanism between atomic vibrations and spin. Furthermore, using this mechanism, they have formulated the amount of spin per unit of time injected from the chiral material into the metal.
The spin-induction phenomenon caused by the chirality of a material is called chirality-induced spin selectivity. Chirality-induced spin selectivity has been actively studied in recent years as a new operating principle for spintronic devices, and this research represents an important step toward elucidating its expression mechanism. Additionally, while heavy elements have been required for high-performance spintronic devices, the chirality-induced spin generation mechanism elucidated in this study does not require heavy elements. Therefore, it is expected to greatly contribute to the development of environmentally friendly spintronic devices that do not use heavy elements.
This result was published in the online edition of the American scientific journal *Physical Review Letters* on June 6 (local time).
For the full press release, please see below.