由轨道织构引起的本征自旋和轨道霍尔效应。

Intrinsic Spin and Orbital Hall Effects from Orbital Texture.

机构信息

Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea.

Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.

出版信息

Phys Rev Lett. 2018 Aug 24;121(8):086602. doi: 10.1103/PhysRevLett.121.086602.

DOI:10.1103/PhysRevLett.121.086602

PMID:30192574

Abstract

We show theoretically that both the intrinsic spin Hall effect (SHE) and orbital Hall effect (OHE) can arise in centrosymmetric systems through momentum-space orbital texture, which is ubiquitous even in centrosymmetric systems unlike spin texture. The OHE occurs even without spin-orbit coupling (SOC) and is converted into the SHE through SOC. The resulting spin Hall conductivity is large (comparable to that of Pt) but depends on the SOC strength in a nonmonotonic way. This mechanism is stable against orbital quenching. This work suggests a path for an ongoing search for materials with stronger SHE. It also calls for experimental efforts to probe orbital degrees of freedom in the OHE and SHE. Possible ways for experimental detection are briefly discussed.

摘要

我们从理论上证明，即使在没有自旋各向异性的情况下，通过动量空间轨道织构，中心对称系统中也会同时出现固有自旋霍尔效应（SHE）和轨道霍尔效应（OHE），而这种轨道织构是普遍存在的，不同于自旋织构。即使没有自旋轨道耦合（SOC），OHE 也会发生，并通过 SOC 转化为 SHE。由此产生的自旋霍尔电导率很大（与 Pt 相当），但与 SOC 强度呈非单调关系。这种机制对轨道猝灭是稳定的。这项工作为寻找具有更强 SHE 的材料提供了一条途径。它还呼吁进行实验努力，以探测 OHE 和 SHE 中的轨道自由度。简要讨论了可能的实验检测方法。