论文标题
单层过渡金属二核苷的内在轨道和自旋大厅效应
Intrinsic orbital and spin Hall effects in monolayer transition metal dichalcogenides
论文作者
论文摘要
轨道大厅效应（OHE）是在存在施加电场的情况下轨道矩的横向流动的现象。由于在布里渊区的单个动量点上存在固有的轨道力矩，在存在净轨道大厅电流的不同方向上流动，因此预计具有反转对称性的固体将表现出强大的OHE。在这里，我们对单层2D过渡金属二分法（TMDC）的效果及其可调节性提供了全面的理解。金属和绝缘TMDC均通过全密度功能的计算，有效的$ d $ band紧密结合模型以及最小的四波段模型来研究山谷点，以捕获系统的关键物理。为了调整OHE，我们检查了孔掺杂的作用以及频带参数的变化，例如。 g。，可以通过应变控制。我们证明，OHE比旋转大厅效应（SHA）更基本的效果，而动量空间轨道矩在存在自旋轨道耦合的情况下会诱导旋转力矩，从而导致SHE。此处描述的OHE的物理学与二维材料有关，其倒置对称性通常，甚至超出了TMDC，为将来的研究提供了广泛的平台。
Orbital Hall effect (OHE) is the phenomenon of transverse flow of orbital moment in presence of an applied electric field. Solids with broken inversion symmetry are expected to exhibit a strong OHE due to the presence of an intrinsic orbital moment at individual momentum points in the Brillouin zone, which in presence of an applied electric field, flows in different directions causing a net orbital Hall current. Here we provide a comprehensive understanding of the effect and its tunability in the monolayer 2D transition metal dichalcogenides (TMDCs). Both metallic and insulating TMDCs are investigated from full density-functional calculations, effective $d$-band tight-binding models, as well as a minimal four-band model for the valley points that captures the key physics of the system. For the tuning of the OHE, we examine the role of hole doping as well as the change in the band parameters, which, e. g., can be controlled by strain. We demonstrate that the OHE is a more fundamental effect than the spin Hall effect (SHE), with the momentum-space orbital moments inducing a spin moment in the presence of the spin-orbit coupling, leading to the SHE. The physics of the OHE, described here, is relevant for 2D materials with broken inversion symmetry in general, even beyond the TMDCs, providing a broad platform for future research.
