论文标题
单层WTE $ _2 $的量子旋转厅阶段的热鲁棒性
Thermal robustness of the quantum spin Hall phase in monolayer WTe$_2$
论文作者
论文摘要
单层1T'-wte $ _2 $是第一个二维晶体，在该晶体中观察到了量子旋转厅阶段。此外，最近的实验和理论建模还报告了强大的激子绝缘阶段的存在。虽然第一原理通过混合功能和低温下的几个测量结果表明存在50 MEV的频带间隙，但实验可以证实只有高达100 k的螺旋边缘状态。在这里，我们使用第一原则模拟了温度对单层1T'-WTE $ _2 $的电子结构的效果，并考虑了$ _2 $的贡献 - 以及贡献的贡献和贡献。首先，我们表明热膨胀很弱，但倾向于增加间接带隙。然后，我们使用非扰动方法来计算电子 - 音波偶联对频带结构的影响，并观察到随温度升高的频带反转的少量降低。值得注意的是，发现拓扑阶段和有限间隙的存在对于直至室温和高于室温的热效应尤其强大。
Monolayer 1T'-WTe$_2$ has been the first two-dimensional crystal where a quantum spin Hall phase was experimentally observed. In addition, recent experiments and theoretical modeling reported the presence of a robust excitonic insulating phase. While first-principles calculations with hybrid functionals and several measurements at low temperatures suggest the presence of a band gap of the order of 50 meV, experiments could confirm the presence of the helical edge states only up to 100 K. Here, we study with first-principle simulations the temperature effects on the electronic structure of monolayer 1T'-WTe$_2$ and consider the contributions of both thermal expansion and electron-phonon coupling. First, we show that thermal expansion is weak but tends to increase the indirect band gap. Then, we calculate the effect of electron-phonon coupling on the band structure with non-perturbative methods and observe a small reduction of the band inversion with increasing temperature. Notably, the topological phase and the presence of a finite gap are found to be particularly robust to thermal effects up to and above room temperature.
