Theory of spin dynamics induced by temperature gradient

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K13508
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Institute for Molecular Science (2019-2021); Institute of Physical and Chemical Research (2018)
• Principal Investigator: Shitade Atsuo 分子科学研究所, 理論・計算分子科学研究領域, 助教 (20747860)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: スピントロニクス / 多極子 / 磁気四極子 / 電気磁気効果 / カイラル量子異常 / カイラル渦効果 / 軸性磁気効果 / カイラリティ誘起スピン選択性

Outline of Final Research Achievements

We formulated the magnetic quadrupole moment in crystals quantum-mechanically. We proposed the gravitomagnetoelectric effect in which the magnetization is induced by a temperature gradient. In order to calculate this susceptibility, we need to subtract the magnetic quadrupole moment from the Kubo formula.
Regardind the chiral vortical and axial magnetic effects originating from the chiral anomaly, we proved that the resulting currents are magnetization currents that cannot be observed in transport experiments.
We found a novel spin-orbit coupling that is enhanced in nanoscale molecules in the context of the chirality-induced spin selectivity.

Free Research Field

物性理論

Academic Significance and Societal Importance of the Research Achievements

電気磁気効果は古くから知られている交差相関応答であり，電場で磁性を制御できるという点で応用上も重要である．本研究によって温度勾配によっても磁性を制御できることが示され，磁気四極子モーメントの重要性も明らかになった．
また，カイラル量子異常に由来する異常輸送現象に関する知見は高エネルギー物理における重イオン衝突実験の解釈にも影響を与える．
スピン軌道相互作用はさまざまな物性をもたらすものであり，新奇のスピン軌道相互作用は見いだされたことはそれだけで意義がある．