Park Sungjoon, Nagaosa Naoto, Yang Bohm-Jung
Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Korea.
Nano Lett. 2020 Apr 8;20(4):2741-2746. doi: 10.1021/acs.nanolett.0c00363. Epub 2020 Mar 4.
We theoretically study the intrinsic thermal Hall and spin Nernst effect in collinear ferrimagnets on a honeycomb lattice with broken inversion symmetry. The broken inversion symmetry allows in-plane Dzyaloshinskii-Moriya interaction between the nearest neighbors, which does not affect the linear spin wave theory. However, the Dzyaloshinskii-Moriya interaction induces large Berry curvature in the magnetoelastic excitations through the magnon-phonon interaction (MPI) to produce thermal Hall current. Furthermore, the magnetoelastic excitations transport spin, which is inherited from the magnons. Therefore, spin Nernst current accompanies the thermal Hall current. Because the MPI does not conserve the spin, we examine the spatial distribution of spin induced by a thermal gradient in the system having a stripe geometry. We find that spin is accumulated at the edges, reflecting the spin Nernst current. We also find that the total spin of the system-and, therefore, the magnetization-is changed, because of the thermal gradient and MPI.
我们从理论上研究了具有破缺反演对称性的蜂窝晶格上共线亚铁磁体中的本征热霍尔效应和自旋能斯特效应。破缺的反演对称性允许最近邻之间存在面内的Dzyaloshinskii-Moriya相互作用，这并不影响线性自旋波理论。然而，Dzyaloshinskii-Moriya相互作用通过磁振子-声子相互作用（MPI）在磁弹性激发中诱导出大的贝里曲率，从而产生热霍尔电流。此外，磁弹性激发传输自旋，该自旋继承自磁振子。因此，自旋能斯特电流伴随着热霍尔电流。由于MPI不守恒自旋，我们研究了具有条纹几何形状的系统中由热梯度诱导的自旋的空间分布。我们发现自旋在边缘处积累，这反映了自旋能斯特电流。我们还发现，由于热梯度和MPI，系统的总自旋以及因此的磁化强度发生了变化。
