论文标题
Quintuple层耦合和拓扑相变的拓扑拓扑拓扑绝缘子
Inter-quintuple layer coupling and topological phase transitions in the chalcogenide topological insulators
论文作者
论文摘要
3D拓扑绝缘子中的驱动量子相变提供了调整拓扑状态及其特性的途径。我们使用基于DFT的计算来系统地研究BI $ _2 $ SE $ _3 $，SB $ _2 $ SE $ _3 $，BI $ _2 $ _2 $ _2 $ _3 $和SB $ _2 $ _2 $ _2 $ _3 $的拓扑相变的拓扑相变。这样可以确保在各向异性应力和应变下没有净静水压力，并可以清楚地识别导致过渡的物理。作为$ c/a $的函数，所有这些材料均表现出五重级层（QLS）的结构和电子稳定性，以及Quintuple层间距离的准线性行为，以及拓扑过渡附近的能量差距。我们的结果表明，过渡主要由QL Inter-QL物理学控制，即通过在附近的五五头层中的外部原子片之间竞争库仑和范德华的相互作用。我们讨论了通过合金调整结果对拓扑调整的含义。
Driving quantum phase transitions in the 3D topological insulators offers pathways to tuning the topological states and their properties. We use DFT-based calculations to systematically investigate topological phase transitions in Bi$_2$Se$_3$, Sb$_2$Se$_3$, Bi$_2$Te$_3$ and Sb$_2$Te$_3$ by varying the $c/a$ ratio of lattice constants. This ensures no net hydrostatic pressure under anisotropic stress and strain and allows a clear identification of the physics leading to the transition. As a function of $c/a$, all of these materials exhibit structural and electronic stability of the quintuple layers (QLs), and quasi-linear behavior of both the inter-quintuple layer distance and the energy gap near the topological transition. Our results show that the transition is predominantly controlled by the inter-QL physics, namely by competing Coulomb and van der Waals interactions between the outer atomic sheets in neighboring quintuple layers. We discuss the implications of our results for topological tuning by alloying.
