论文标题
Antiperovskites中的高阶拓扑绝缘子
Higher-order topological insulators in antiperovskites
论文作者
论文摘要
我们预测，一个Antiperovskite材料家族实现了一个高阶拓扑阶段，其特征是先前引入的$ \ Mathbb {z} _4 $ index。紧密的结合模型和$ K \ CDOT P $模型用于捕获这些材料的散装，表面和铰链状态的物理。对于紧密结合模型，获得了高阶和弱拓扑不变的相位图。还讨论了镜子Chern号码。为了在存在镜面表面状态的情况下揭示无间隙铰链状态，通过计算提出并确认了几种打开表面间隙的方法，包括裂解晶体以揭示低对称表面，建立异质结构并施加应变。打开表面间隙后，我们能够通过计算中间隙状态的动量空间带结构和实际空间分布来研究铰链状态。
We predict that a family of antiperovskite materials realize a higher order topological insulator phase, characterized by a previously introduced $\mathbb{Z}_4$ index. A tight binding model and a $k\cdot p$ model are used to capture the physics of the bulk, surface and hinge states of these materials. A phase diagram of the higher order and weak topological invariants is obtained for the tight binding model. The mirror Chern number is also discussed. In order to reveal the gapless hinge states in the presence of mirror Chern surface states, several ways of opening the surface gap are proposed and confirmed by calculation, including cleaving the crystal to reveal a low-symmetry surface, building a heterostructure, and applying strain. Upon opening the surface gap, we are able to study the hinge states by computing the momentum space band structure and real space distribution of mid-gap states.
