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船戸 匠*; 松尾 衛
Journal of Magnetism and Magnetic Materials, 540, p.168436_1 - 168436_7, 2021/12
被引用回数：3 パーセンタイル：24.56(Materials Science, Multidisciplinary)We theoretically study the mechanical induction of the spin density via the Rashba spin--orbit interaction (SOI). The spin density in the linear response to lattice distortion dynamics is calculated based on the microscopic theory. We reveal that there are two mechanisms of spin induction: one is the acoustic Edelstein effect (AEE) from the acceleration of the lattice dynamics and the other is caused by the Rashba spin--vorticity coupling (RSVC). We find that the AEE induces a more efficient spin-to-charge conversion in comparison with the conventional electric Edelstein effect. The induced spin density due to the RSVC is expressed as a Berry curvature-like quantity; therefore, it can be attributed to the spatial symmetry breaking due to the Rashba SOI. Our work demonstrates high-efficiency spin generation in Rashba systems.
山本 剛史*; 加藤 岳生*; 松尾 衛
Physical Review B, 104(12), p.L121401_1 - L121401_5, 2021/09
被引用回数：5 パーセンタイル：43.44(Materials Science, Multidisciplinary)We investigate the spin Seebeck effect and spin pumping in a junction between a ferromagnetic insulator and a magnetic impurity deposited on a normal metal. By performing a numerical renormalization group calculation, we show that spin current is enhanced by the Kondo effect. This spin current is suppressed by an increase in temperature or a magnetic field comparable to the Kondo temperature. Our results indicate that spin transport can be a direct probe of spin excitation in strongly correlated systems.
山 正樹*; 立野 雅大*; 加藤 岳生*; 松尾 衛
Physical Review B, 104(5), p.054410_1 - 054410_9, 2021/08
被引用回数：7 パーセンタイル：55.98(Materials Science, Multidisciplinary)We theoretically consider spin pumping in a junction between a ferromagnetic insulator (FI) and a two-dimensional electron gas (2DEG) in which the Rashba and Dresselhaus spin-orbit interactions coexist. Using second-order perturbation theory, we derive an increase in linewidth in the case of an interfacial exchange coupling in a ferromagnetic resonance (FMR) experiment. We clarify how the enhancement of Gilbert damping depends on the resonant frequency and spin orientation of the FI. We show that this setup of an FMR experiment can provide information on the spin texture of 2DEG at the Fermi surface.
船戸 匠*; 松尾 衛
Physical Review B, 104(6), p.L060412_1 - L060412_5, 2021/08
被引用回数：3 パーセンタイル：26.56(Materials Science, Multidisciplinary)We theoretically study spin transport in two- or three-dimensional Rashba systems dynamically distorted by surface acoustic waves. The spin currents in the linear response to lattice distortion dynamics are calculated on the basis of a microscopic theory combined with local coordinate transformations. As a result, we find a mechanism of direct spin-current generation from lattice distortion not associated with a charge current or spin accumulation. Moreover, the in-plane helicity currents are generated by shear surface acoustic waves via the present mechanism. The generated helicity currents are not parallel to the vorticity of the lattice, and cannot be created with the conventional methods. Thus, our findings offer an alternative functionality of the conventional Rashba systems in the field of spintronics.
仲田 光樹; 大沼 悠一*; 松尾 衛*
Physical Review B, 99(13), p.134403_1 - 134403_7, 2019/04
被引用回数：4 パーセンタイル：21.61(Materials Science, Multidisciplinary)マグノン流に内在する量子力学的性質「量子ゆらぎ物性」をスピン流雑音の観点から理論的に研究し、マグノン流の非可換性由来の非対称マグノン流量子雑音を解明した。
仲田 光樹; 大沼 悠一*; 松尾 衛*
Physical Review B, 98(9), p.094430_1 - 094430_8, 2018/09
被引用回数：11 パーセンタイル：48.71(Materials Science, Multidisciplinary)強磁性絶縁体中のマグノンがもたらすスピン流/熱流に着目し、物質によらない「ゆらぎの普遍的熱磁気関係式」を紹介する。マグノン輸送に内在する量子統計力学的効果「ゆらぎ」を、マグノン流ノイズ(雑音)の視点から従来のマグノンWiedemann-Franz則に取り込み、「熱-磁気-ゆらぎ」三者を紡ぐ「ゆらぎのマグノンWiedemann-Franz則」を提示する。さらに、熱ノイズ(平衡ノイズ)と比較して非平衡ノイズが支配的となるマグノンショットノイズ領域に着目し、線形応答領域のみならず非線形応答領域においても成立するスピンFano因子の普遍的なふるまいを紹介する。
