Shao Ding-Fu, Zhang Shu-Hui, Gurung Gautam, Yang Wen, Tsymbal Evgeny Y
Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588-0299, USA.
College of Mathematics and Physics, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
Phys Rev Lett. 2020 Feb 14;124(6):067203. doi: 10.1103/PhysRevLett.124.067203.
Antiferromagnetic (AFM) spintronics exploits the Néel vector as a state variable for novel spintronic devices. Recent studies have shown that the fieldlike and antidamping spin-orbit torques (SOTs) can be used to switch the Néel vector in antiferromagnets with proper symmetries. However, the precise detection of the Néel vector remains a challenging problem. In this Letter, we predict that the nonlinear anomalous Hall effect (AHE) can be used to detect the Néel vector in most compensated antiferromagnets supporting the antidamping SOT. We show that the magnetic crystal group symmetry of these antiferromagnets combined with spin-orbit coupling produce a sizable Berry curvature dipole and hence the nonlinear AHE. As a specific example, we consider the half-Heusler alloy CuMnSb, in which the Néel vector can be switched by the antidamping SOT. Based on density-functional theory calculations, we show that the nonlinear AHE in CuMnSb results in a measurable Hall voltage under conventional experimental conditions. The strong dependence of the Berry curvature dipole on the Néel vector orientation provides a new detection scheme of the Néel vector based on the nonlinear AHE. Our predictions enrich the material platform for studying nontrivial phenomena associated with the Berry curvature and broaden the range of materials useful for AFM spintronics.
反铁磁自旋电子学利用奈尔矢量作为新型自旋电子器件的状态变量。最近的研究表明，类场和反阻尼自旋轨道转矩（SOTs）可用于在具有适当对称性的反铁磁体中切换奈尔矢量。然而，精确检测奈尔矢量仍然是一个具有挑战性的问题。在本信函中，我们预测非线性反常霍尔效应（AHE）可用于在大多数支持反阻尼SOT的补偿反铁磁体中检测奈尔矢量。我们表明，这些反铁磁体的磁晶体群对称性与自旋轨道耦合相结合会产生可观的贝里曲率偶极子，从而产生非线性AHE。作为一个具体例子，我们考虑半赫斯勒合金CuMnSb，其中奈尔矢量可通过反阻尼SOT进行切换。基于密度泛函理论计算，我们表明，在传统实验条件下，CuMnSb中的非线性AHE会导致可测量的霍尔电压。贝里曲率偶极子对奈尔矢量取向的强烈依赖性提供了一种基于非线性AHE的奈尔矢量新检测方案。我们的预测丰富了用于研究与贝里曲率相关的非平凡现象的材料平台，并拓宽了对反铁磁自旋电子学有用的材料范围。
