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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:23.8(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:42.31(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:54.88(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:25.71(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*
no journal, ,
Keldysh形式(Green関数法)を用い、Fermi粒子系(電子系)に対する「Boltzmann-Langevinアプローチ」をBose粒子系(マグノン系)に発展・適用させ、量子統計性に依らない普遍的輸送物性をショットノイズ(非平衡雑音)の観点から明らかにする。
仲田 光樹; 大沼 悠一*; 松尾 衛*
no journal, ,
電子系で培われた「非平衡雑音(電流ノイズ)」に関する知見を、Keldysh形式(Green関数法)を通じて「スピン流」、特に磁性絶縁体中を流れる「マグノン流(スピン波スピン流)」に適用・応用して得られた、内在するスピン流量子物性、量子統計性に依らない普遍的輸送物性について議論する。