Valleytronics公司
自旋电子学
凝聚态物理
量子自旋霍尔效应
拓扑绝缘体
物理
Berry连接和曲率
自旋(空气动力学)
自旋霍尔效应
量子反常霍尔效应
量子霍尔效应
自旋极化
拓扑(电路)
量子力学
几何相位
铁磁性
热力学
组合数学
数学
电子
作者
San‐Dong Guo,Yutong Zhu
标识
DOI:10.1088/1361-648x/ac5313
摘要
Achieving combination of spin and valley polarized states with topological insulating phase is pregnant to promote the fantastic integration of topological physics, spintronics and valleytronics. In this work, a spin-valley-coupled quantum spin Hall insulator (svc-QSHI) is predicted in Janus monolayer CSb1.5Bi1.5with dynamic, mechanical and thermal stabilities. Calculated results show that the CSb1.5Bi1.5is a direct band gap semiconductor with and without spin-orbit coupling, and the conduction-band minimum and valence-band maximum are at valley point. The inequivalent valleys have opposite Berry curvature and spin moment, which can produce a spin-valley Hall effect. In the center of Brillouin zone, a Rashba-type spin splitting can be observed due to missing horizontal mirror symmetry. The topological characteristic of CSb1.5Bi1.5is confirmed by theZ2invariant and topological protected conducting helical edge states. Moreover, the CSb1.5Bi1.5shows unique Rashba-splitting edge states. Both energy band gap and spin-splitting at the valley point are larger than the thermal energy of room temperature (25 meV) with generalized gradient approximation level, which is very important at room temperature for device applications. It is proved that the spin-valley-coupling and nontrivial quantum spin Hall state are robust again biaxial strain. Our work may provide a new platform to achieve integration of topological physics, spintronics and valleytronics.
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