论文标题
高阶拓扑结晶绝缘阶段和拓扑电气中的铰链电荷
Higher-Order Topological Crystalline Insulating Phase and Quantized Hinge Charge in Topological Electride Apatite
论文作者
论文摘要
在高阶拓扑绝缘子中，散装和表面电子状态被覆盖，而在空间对称性的保护状态下出现无间隙的铰链状态。在这里，我们通过Ab IST计算显示LA磷灰石电气是一种高阶拓扑晶体绝缘子。它是一维电气，其中沿$ C $轴支撑阴离子电子的一维间隙空心，并且这些一维通道中的电子状态由一维su-schrieffer-Heeger模型很好地近似。当晶体被切成六角形棱镜时，120 $^\ circ $ hinges支持无间隙铰链状态，其填充量为2/3。填充的量化来自拓扑来源。我们发现，填充的量化值取决于构成晶体的基本块。磷灰石由三角形块组成，这对于在铰链时给出非平凡的分数电荷至关重要。
In higher-order topological insulators, bulk and surface electronic states are gapped, while there appear gapless hinge states protected by spatial symmetry. Here we show by ab initio calculations that the La apatite electride is a higher-order topological crystalline insulator. It is a one-dimensional electride, in which the one-dimensional interstitial hollows along the $c$ axis support anionic electrons, and the electronic states in these one-dimensional channels are well approximated by the one-dimensional Su-Schrieffer-Heeger model. When the crystal is cleaved into a hexagonal prism, the 120$^\circ$ hinges support gapless hinge states, with their filling quantized to be 2/3. This quantization of the filling comes from a topological origin. We find that the quantized value of the filling depends on the fundamental blocks that constitute the crystal. The apatite consists of the triangular blocks, which is crucial for giving nontrivial fractional charge at the hinge.
