Possible realization of high-temperature and multichannel quantum anomalous Hall effect in graphene/CrBr3 heterostructures under pressure
Possible realization of high-temperature and multichannel quantum anomalous Hall effect in graphene/CrBr3 heterostructures under pressure
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压力下石墨烯/CrBr3异质结构高温多通道量子反常霍尔效应的可能实现
DOI：
10.1039/c9cp03219c
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Xiaohong Xu
中科院分区：
文献类型：
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作者：
Huisheng Zhang;Yaohui Ning;Wenjia Yang;Jiayong Zhang;Ruiqiang Zhang;Xiaohong Xu
最近对石墨烯和超薄 CrBr3 薄膜形成的铁磁范德华异质结构中的磁力辅助隧道效应的研究（D. Ghazaryan 等人，Nat. Electron., 2018, 1, 344）为探索新颖的量子现象，特别是实现基于石墨烯的量子反常霍尔效应（QAHE）提供了更广泛的机会。基于第一性原理方法，我们揭示了三种类型的石墨烯/CrBr3（Gr/CrBr3）异质结构由于这些异质系统界面处的强电荷转移而表现出金属能带行为。值得注意的是，压力诱导的 QAHE 可以在 Gr/CrBr3 和 CrBr3/Gr/CrBr3 系统中实现。进一步的低能k·p模型分析表明，非平凡的拓扑性质主要归因于Rashba自旋轨道耦合（SOC），而不是石墨烯固有的SOC。此外，提出了由Gr/CrBr3和普通绝缘体（例如六方氮化硼）层组成的超晶格中的多通道器件原型。我们的工作为在石墨烯基异质结构中实现高温多通道QAHE提供了实验上可行的方案。
The recent studies of magno-assisted tunnelling in ferromagnetic van der Waals heterostructures formed by graphene and ultrathin CrBr3 films (D. Ghazaryan et al., Nat. Electron., 2018, 1, 344) offer broader opportunities for exploration of novel quantum phenomena, especially for realizing the graphene-based quantum anomalous Hall effect (QAHE). Based on first-principles approaches, we reveal that three types of graphene/CrBr3 (Gr/CrBr3) heterostructures exhibit metallic band behavior due to strong charge-transfer at the interfaces of these heterosystems. Remarkably, the pressure-induced QAHE can be achieved in Gr/CrBr3 and CrBr3/Gr/CrBr3 systems. Further low energy k·p model analyses show that the nontrivial topological properties are mainly attributed to the Rashba spin–orbit coupling (SOC), but not to the intrinsic SOC of graphene. Moreover, a multichannel device prototype is proposed in the superlattices composed of Gr/CrBr3 and normal insulator (such as hexagonal boron nitride) layers. Our work provides an experimentally feasible scheme for realizing the high-temperature and multichannel QAHE in graphene-based heterostructures.