Mawrie Alestin
Department of Physics, Indian Institute of Technology Indore, Simrol, Indore-453552, India.
J Phys Condens Matter. 2022 Apr 7;34(24). doi: 10.1088/1361-648X/ac5fd7.
The quantum spin Hall (QSH) states discovered in an inverted band of InAs/GaSb and HgTe/CdTe quantum wells categorize them among the very superior candidates for topological insulators. In the presence of a magnetic field, these QSH states persist up to a magnetic field equal to the critical field, beyond which the edge states would consist of normal quantum Hall (QH) states. We provide the expression of this critical field which is found consistent with some previous literature. The critical field partitioned the spectrum into two types of quantum states, viz, the QSH and QH states. We present a theoretical study of the magnetotransport properties based on the Bernevig-Hughes-Zhang Hamiltonian that describes these QSH states. Our results of the Hall conductivity show the different responses at these two different topological regions. Around the low Fermi energy level, the system has a high Hall conductivity in the QH region, while the same is less dominant in the QSH region. Our results of the Hall conductivity thus help differentiate the type topological phase of the given quantum well.
在InAs/GaSb和HgTe/CdTe量子阱的反转能带中发现的量子自旋霍尔（QSH）态，使它们成为拓扑绝缘体的非常优秀的候选者。在存在磁场的情况下，这些QSH态一直持续到等于临界场的磁场，超过这个磁场，边缘态将由正常量子霍尔（QH）态组成。我们给出了这个临界场的表达式，发现它与一些先前的文献一致。临界场将能谱分为两种量子态，即QSH态和QH态。我们基于描述这些QSH态的Bernevig-Hughes-Zhang哈密顿量，对磁输运性质进行了理论研究。我们的霍尔电导率结果显示了在这两个不同拓扑区域的不同响应。在低费米能级附近，系统在QH区域具有高霍尔电导率，而在QSH区域则不那么显著。因此，我们的霍尔电导率结果有助于区分给定量子阱的拓扑相类型。
