Li Peng, Ding Jinjun, Zhang Steven S-L, Kally James, Pillsbury Timothy, Heinonen Olle G, Rimal Gaurab, Bi Chong, DeMann August, Field Stuart B, Wang Weigang, Tang Jinke, Jiang Jidong Samuel, Hoffmann Axel, Samarth Nitin, Wu Mingzhong
Department of Physics, Colorado State University, Fort Collins, Colorado 80523, United States.
Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.
Nano Lett. 2021 Jan 13;21(1):84-90. doi: 10.1021/acs.nanolett.0c03195. Epub 2020 Dec 23.
A topological insulator (TI) interfaced with a magnetic insulator (MI) may host an anomalous Hall effect (AHE), a quantum AHE, and a topological Hall effect (THE). Recent studies, however, suggest that coexisting magnetic phases in TI/MI heterostructures may result in an AHE-associated response that resembles a THE but in fact is not. This Letter reports a genuine THE in a TI/MI structure that has only one magnetic phase. The structure shows a THE in the temperature range of = 2-3 K and an AHE at = 80-300 K. Over = 3-80 K, the two effects coexist but show opposite temperature dependencies. Control measurements, calculations, and simulations together suggest that the observed THE originates from skyrmions, rather than the coexistence of two AHE responses. The skyrmions are formed due to a Dzyaloshinskii-Moriya interaction (DMI) at the interface; the DMI strength estimated is substantially higher than that in heavy metal-based systems.
与磁绝缘体（MI）界面耦合的拓扑绝缘体（TI）可能会呈现反常霍尔效应（AHE）、量子反常霍尔效应以及拓扑霍尔效应（THE）。然而，近期研究表明，TI/MI异质结构中共存的磁相可能会导致一种与AHE相关的响应，该响应看似是THE，但实际上并非如此。本文报道了一种仅具有单一磁相的TI/MI结构中的真正的THE。该结构在2 - 3 K的温度范围内呈现出THE，在80 - 300 K时呈现出AHE。在3 - 80 K范围内，这两种效应共存，但呈现出相反的温度依赖性。对照测量、计算和模拟共同表明，观测到的THE源自斯格明子，而非两种AHE响应的共存。斯格明子是由于界面处的Dzyaloshinskii-Moriya相互作用（DMI）形成的；估计的DMI强度显著高于基于重金属的系统。
