Dirac-electron-mediated magnetic proximity effect in topological insulator/magnetic insulator heterostructures
Dirac-electron-mediated magnetic proximity effect in topological insulator/magnetic insulator heterostructures
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DOI：
10.1103/physrevb.96.201301
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发表时间：
2017-06
影响因子：
3.7
通讯作者：
Mingda Li;Qichen Song;Weiwei Zhao;J. Garlow;Te-Huan Liu;Lijun Wu;Yimei Zhu;J. Moodera;M. Chan-M.-Cha
中科院分区：
文献类型：
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作者：
Mingda Li;Qichen Song;Weiwei Zhao;J. Garlow;Te-Huan Liu;Lijun Wu;Yimei Zhu;J. Moodera;M. Chan-M.-Cha
拓扑绝缘子/磁绝缘子异质结构中无耗散手性边缘电流的可能实现是基于拓扑绝缘子的狄拉克表面态主导界面磁邻近交换耦合的条件。本文报道了用极化中子反射法观察了块状绝缘拓扑绝缘体（Bi$_{0.2}$Sb$_{0.8}$）$_{2}$Te$_{3}$ /磁绝缘体EuS异质结构中Dirac电子介导的磁邻近效应。我们可以通过一个电子后门来调节拓扑绝缘体的费米能级，使其接近电荷中性点，从而最大限度地提高邻近感应磁性。建立了一种基于抗磁筛选的现象模型来解释高载流子密度下邻近感应磁的抑制。我们的工作为利用拓扑绝缘体/磁绝缘体异质界面的磁邻近效应用于低功率自旋电子应用铺平了道路。
The possible realization of dissipationless chiral edge current in a topological insulator / magnetic insulator heterostructure is based on the condition that the magnetic proximity exchange coupling at the interface is dominated by the Dirac surface states of the topological insulator. Here we report a polarized neutron reflectometry observation of Dirac electrons mediated magnetic proximity effect in a bulk-insulating topological insulator (Bi$_{0.2}$Sb$_{0.8}$)$_{2}$Te$_{3}$ / magnetic insulator EuS heterostructure. We are able to maximize the proximity induced magnetism by applying an electrical back gate to tune the Fermi level of topological insulator to be close to the charge neutral point. A phenomenological model based on diamagnetic screening is developed to explain the suppressed proximity induced magnetism at high carrier density. Our work paves the way to utilize the magnetic proximity effect at the topological insulator/magnetic insulator hetero-interface for low-power spintronic applications.