论文标题
$ GW $研究IV组的压力诱导的拓扑绝缘体过渡
$GW$ study of pressure-induced topological insulator transition in group IV-tellurides
论文作者
论文摘要
我们使用密度函数理论（DFT）和$ G_0W_0 $方法计算狭窄差距半导体，SNTE和GETE的电子结构。在DFT中，我们显示了使用常规半变元相关近似获得的频带排序对于SNTE和GETE是正确的，但对于PBTE而言是错误的。恢复了高对称点L处的正确带订单，添加$ g_0w_0 $ quasiparticle校正。但是，由于DFT单粒子状态的错误轨道特征在接近L的频段边缘处产生频段结构中的人工制品。我们表明，为了纠正这些伪像，足以考虑$ G_0W_0 $自我启动与这些状态的$ G_0W_0 $ eNerergy的异位元素。我们还研究了这些材料带隙的压力依赖性，以及从微不足道到条带结构的非平凡拓扑的过渡的可能性。对于PBTE，我们预测频带的交叉和拓扑转变发生在4.8 GPA左右。对于GetE，我们估计在约束的立方相中，拓扑过渡发生在1.9 GPa，其压力低于从rombohedral到立方的结构相过渡的压力。 SNTE是一种在环境压力下的结晶拓扑绝缘子，在大约$ 10 \％$的体积膨胀下，向微不足道的拓扑过渡将发生。
We calculate the electronic structure of the narrow gap semiconductors PbTe, SnTe and GeTe in the cubic phase using density functional theory (DFT) and the $G_0W_0$ method. Within DFT, we show that the band ordering obtained with a conventional semilocal exchange-correlation approximation is correct for SnTe and GeTe but wrong for PbTe. The correct band ordering at the high-symmetry point L is recovered adding $G_0W_0$ quasiparticle corrections. However, one-shot $G_0W_0$ produces artifacts in the band structure due to the wrong orbital character of the DFT single-particle states at the band edges close to L. We show that in order to correct these artifacts it is enough to consider the off-diagonal elements of the $G_0W_0$ self-energy corresponding to these states. We also investigate the pressure dependence of the band gap for these materials and the possibility of a transition from a trivial to a non-trivial topology of the band structure. For PbTe, we predict the band crossover and topological transition to occur at around 4.8 GPa. For GeTe, we estimate the topological transition to occur at 1.9 GPa in the constrained cubic phase, a pressure lower than the one of the structural phase transition from rombohedral to cubic. SnTe is a crystalline topological insulator at ambient pressure, and the transition into a trivial topology would take place under a volume expansion of approximately $10\%$.
