Park Hyeon-Jong, Ko Hye-Won, Go Gyungchoon, Oh Jung Hyun, Kim Kyoung-Whan, Lee Kyung-Jin
KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea.
Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
Phys Rev Lett. 2022 Jul 15;129(3):037202. doi: 10.1103/PhysRevLett.129.037202.
We theoretically demonstrate the spin swapping effect of band structure origin in centrosymmetric ferromagnets. It is mediated by an orbital degree of freedom but does not require inversion asymmetry or impurity spin-orbit scattering. Analytic and tight-binding models reveal that it originates mainly from k points where bands with different spins and different orbitals are nearly degenerate, and thus it has no counterpart in normal metals. First-principle calculations for centrosymmetric 3d transition-metal ferromagnets show that the spin swapping conductivity of band structure origin can be comparable in magnitude to the intrinsic spin Hall conductivity of Pt. Our theory generalizes transverse spin currents generated by ferromagnets and emphasizes the important role of the orbital degree of freedom in describing spin-orbit-coupled transport in centrosymmetric materials.
我们从理论上证明了中心对称铁磁体中能带结构起源的自旋交换效应。它由轨道自由度介导，但不需要反演不对称性或杂质自旋 - 轨道散射。解析模型和紧束缚模型表明，它主要起源于具有不同自旋和不同轨道的能带近乎简并的k点，因此在普通金属中不存在类似情况。对中心对称3d过渡金属铁磁体的第一性原理计算表明，能带结构起源的自旋交换电导率在量级上可与Pt的本征自旋霍尔电导率相媲美。我们的理论推广了铁磁体产生的横向自旋电流，并强调了轨道自由度在描述中心对称材料中自旋 - 轨道耦合输运方面的重要作用。
