论文标题
Rashba诱导的抗铁磁CRI3双层中的旋转质地和自旋层锁定效果
Rashba-induced spin texture and spin-layer-locking effects in the antiferromagnetic CrI3 bilayer
论文作者
论文摘要
抗铁磁（AFM）CRI $ _3 $ BILAYER是Van der Waals 2d半导体的特别有趣的代表，目前正在研究其磁性及其在Spintronics中的潜力。使用从头算密度功能理论计算，我们研究了AFM CRI $ _3 $ biLayer的（双重变性）最高价带的动量空间中的自旋纹理，其Cr旋转矩垂直于层。我们发现，在布里渊区的主要中央部分的存在，是两层的RASHBA内平面旋转质地的平面内旋转纹理，这是由作用在每一层上的固有的局部电场。为了研究波形的层隔离，我们应用了一个小电场，该电场根据其层占用率将堕落状态分裂。我们发现，最高价带的波函数是层分析的，仅属于两个面积内旋转纹理的两个层之一，并且隔离发生在几乎整个布里群区域上。平面内旋转的相应层锁定与最高的AFM谱带的分离与价带的其余部分有关。我们解释了乐队的交互如何破坏$ k $，$ k'$和$γ$点的图层锁定。此外，我们比较了我们的AFM双层系统中平面内旋转自旋的层锁定与中心对称非磁性材料中隐藏的自旋极化，指出了隔离机制的差异及其对层锁定的后果。我们注意到，在其他具有强旋转轨耦合和隔离能带的范德华AFM双层中，可能发生与平面内旋转旋转的层锁定的类似RashBA效应。
The antiferromagnetic (AFM) CrI$_3$ bilayer is a particularly interesting representative of van der Waals 2D semiconductors, which are currently being studied for their magnetism and for their potential in spintronics. Using ab initio density-functional theory calculations, we investigate the spin texture in momentum space of the states of the (doubly degenerate) highest valence band of the AFM CrI$_3$ bilayer with Cr-spin moments perpendicular to the layers. We find the existence, in the main central part of the Brillouin zone, of a Rashba in-plane spin texture of opposite signs on the two layers, resulting from the intrinsic local electric fields acting on each layer. To study the layer segregation of the wavefunctions, we apply a small electric field that splits the degenerate states according to their layer occupancy. We find that the wavefunctions of the highest valence band are layer-segregated, belonging to only one of the two layers with opposite in-plane spin textures, and the segregation occurs over nearly the whole Brillouin zone. The corresponding layer locking of the in-plane-canted spin is related to the separation in energy of the highest AFM band from the rest of the valence bands. We explain how the band interactions destroy the layer locking at the $K$, $K'$, and $Γ$ points. Furthermore, we compare the layer locking of the in-plane-canted spin in our AFM bilayer system with the hidden spin polarization in centrosymmetric nonmagnetic materials, pointing out the differences in segregation mechanisms and their consequences for the layer locking. We note that a similar Rashba effect with layer locking of in-plane-canted spin could occur in other van der Waals AFM bilayers with strong spin-orbit coupling and an isolated energy band.
