物理
拓扑(电路)
Chern类
量子反常霍尔效应
Valleytronics公司
拓扑绝缘体
凝聚态物理
几何相位
半金属
量子霍尔效应
磁场
量子力学
带隙
自旋电子学
铁磁性
几何学
组合数学
数学
作者
Vassilios Vargiamidis,P. Vasilopoulos,Neophytos Neophytou
出处
期刊:Physical review
日期:2022-11-28
卷期号:106 (20)
被引量:3
标识
DOI:10.1103/physrevb.106.205416
摘要
We investigate topological phases of monolayer jacutingaite (${\mathrm{Pt}}_{2}{\mathrm{HgSe}}_{3}$) that arise when considering the competing effects of spin-orbit coupling (SOC), magnetic exchange interactions, and staggered sublattice potential $V$. The interplay between the staggered potential and exchange field offers the possibility of attaining different topological phases. By analyzing the Berry curvatures and computing the Chern numbers and Hall conductivities, we demonstrate that the system is time-reversal-symmetry-broken quantum spin Hall insulator when ${m}_{b}<{\ensuremath{\lambda}}_{\mathrm{so}}$, where ${m}_{b}$ is the exchange field operating on the bottom Hg sublattice and ${\ensuremath{\lambda}}_{\mathrm{so}}$ is the intrinsic SOC. For ${m}_{b}>{\ensuremath{\lambda}}_{\mathrm{so}}$ and in the presence of Rashba SOC, we find that the band gap at valley $K({K}^{\ensuremath{'}})$ is topologically trivial (nontrivial) with Chern number $\mathcal{C}=1$ and valley Chern number ${\mathcal{C}}_{v}=\ensuremath{-}1$, indicating that the system is valley-polarized quantum anomalous Hall insulator. We show that the topology of each valley is swapped (the Chern number becomes $\mathcal{C}=\ensuremath{-}1$) by reversing the sign of the exchange field. The system transitions to a valley-polarized metal and quantum valley Hall phase as $V$ increases. Along the phase boundaries, we observe a single Dirac-cone semimetal states. These findings shed more light on the possibility of realizing and controlling topological phases in spintronics and valleytronics devices.
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