Two-dimensional MX Dirac materials and quantum spin Hall insulators with tunable electronic and topological properties
Two-dimensional MX Dirac materials and quantum spin Hall insulators with tunable electronic and topological properties
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DOI：
10.1007/s12274-020-3022-3
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发表时间：
2020-08
期刊：
影响因子：
9.9
通讯作者：
Yan-Fang Zhang;Jinbo Pan;H. Banjade;Jie Yu;Hsin Lin;A. Bansil;S. Du;Q. Yan
中科院分区：
文献类型：
--
作者：
Yan-Fang Zhang;Jinbo Pan;H. Banjade;Jie Yu;Hsin Lin;A. Bansil;S. Du;Q. Yan
我们提出了一类新的二维（2D）狄拉克材料（M = Be, Mg， Zn和Cd， X = Cl， Br和I），它们在大能量尺度（0.8-1.8 eV）和与石墨烯相当的超高费米速度下表现出类似石墨烯的带结构，具有线性分散的狄拉克锥态。自旋轨道耦合打开了相当大的拓扑带隙，因此这些化合物可以有效地归类为量子自旋霍尔绝缘体。发现电子和拓扑性质是高度可调的，并且可以通过阴离子层取代和垂直电场进行调制。该家族的几个成员的电子结构显示了一个接近狄拉克节点能量的范霍夫奇点（VHS）。与vhs相关的态密度增强可能为诱导拓扑超导提供了一种机制。相当大的带隙、超高的载流子迁移率和小的有效质量使MX系列在电子和自旋电子学应用中具有前景。
We propose a novel class of two-dimensional (2D) Dirac materials in the MX family (M = Be, Mg, Zn and Cd, X = Cl, Br and I), which exhibit graphene-like band structures with linearly-dispersing Dirac-cone states over large energy scales (0.8–1.8 eV) and ultra-high Fermi velocities comparable to graphene. Spin-orbit coupling opens sizable topological band gaps so that these compounds can be effectively classified as quantum spin Hall insulators. The electronic and topological properties are found to be highly tunable and amenable to modulation via anion-layer substitution and vertical electric field. Electronic structures of several members of the family are shown to host a Van-Hove singularity (VHS) close to the energy of the Dirac node. The enhanced density-of-states associated with these VHSs could provide a mechanism for inducing topological superconductivity. The presence of sizable band gaps, ultra-high carrier mobilities, and small effective masses makes the MX family promising for electronics and spintronics applications.