Quantum anomalous Hall effect in a three-dimensional topological-insulator?thin-film-ferromagnetic-metal heterostructure
Quantum anomalous Hall effect in a three-dimensional topological-insulator?thin-film-ferromagnetic-metal heterostructure
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三维拓扑绝缘体薄膜铁磁金属异质结构中的量子反常霍尔效应
DOI：
10.1103/physrevb.103.235315
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发表时间：
2021
影响因子：
3.7
通讯作者：
Nomura Kentaro
中科院分区：
文献类型：
--
作者：
Arimoto Katsuhiro;Koretsune Takashi;Nomura Kentaro
我们从理论上证明，三维（3D）拓扑绝缘体（TI）/薄膜铁磁金属（FMM）异质结构有可能成为具有宽全局带隙的量子反常霍尔（QAH）绝缘体。通过研究能带结构和本征态的权重分布，我们证明，由于原始狄拉克点周围能带的杂化，在 3DTI 上附着金属薄膜可以将拓扑非平凡态转移到金属层中。通过引入薄膜层中的磁交换相互作用，我们计算了异质结构的反常霍尔电导率和磁各向异性，表明比普通材料（例如 3DTI 和 3DTI/铁磁绝缘体异质结构的磁性掺杂薄膜）出现了更宽的间隙，实现了 QAH 效应。我们的结果表明，3DTI/薄膜 FMM 异质结构即使在室温下也可以实现 QAH 效应，这将为其他奇异拓扑量子现象的实验实现铺平道路。
We theoretically show that the three-dimensional (3D) topological insulator (TI)/thin-film ferromagnetic metal (FMM) heterostructure is possible to be a quantum anomalous Hall (QAH) insulator with a wide global band gap. Studying the band structure and the weight distributions of eigenstates, we demonstrate that the attachment of a metallic thin film on the 3DTI can shift the topologically nontrivial state into the metal layers due to the hybridization of bands around the original Dirac point. By introducing the magnetic exchange interaction in the thin-film layers, we compute the anomalous Hall conductivity and magnetic anisotropy of the heterostructure to suggest the appearance of a wider gap realizing QAH effect than usual materials, such as magnetically doped thin films of 3DTI and 3DTI/ferromagnetic insulator heterostructures. Our results indicate that the 3DTI/thin-film FMM heterostructure may implement the QAH effect even at room temperature, which will pave the way to the experimental realization of the other exotic topological quantum phenomena.