论文标题
二维轨道活性双分晶格中的拓扑带
Topological bands in two-dimensional orbital-active bipartite lattices
论文作者
论文摘要
寻找大间隙量子自旋大厅（QSH）和量子异常大厅（QAH）绝缘子对于基本和实际利益都很重要。简化的多轨道$ p_x，p_y $ in Honeycomb晶格为QSH状态提供了一个范式，具有原子旋转轨耦合的一阶的增强拓扑间隙。通过使用基本频段表示，我们在一般二维晶格中探索了该机制对于QSH的可行性，并发现具有$ C_ {3V} $或$ C_ {4V} $对称性和退化多孔的两颗粒晶格可以起作用。我们进一步在Honeycomb，Kagome和Square Lattices上提供混凝土紧密结合模型，以证明所需的拓扑物理学。通过将铁磁性引入QSH状态，我们将机制扩展到QAH状态，并增加了差距。当费米水平仅用于蜂窝晶格，但在某些其他晶格的某些分数填充时，就可以实现QSH和QAH状态。最后，我们简要讨论了这种机制的可能物质场所。
The search for large gap quantum spin Hall (QSH) and quantum anomalous Hall (QAH) insulators is important both for fundamental and practical interests. The degenerate multi-orbitals $p_x,p_y$ in honeycomb lattice provides a paradigm for QSH state with a boosted topological gap of the first order in atomic spin-orbit coupling. By using elementary band representation, we explore the feasibility of this mechanism for QSH in general two-dimensional lattices, and find that the biparticle lattices with $C_{3v}$ or $C_{4v}$ symmetry and degenerate multi-orbitals could work. We further provide concrete tight-binding models on honeycomb, kagome and square lattices to demonstrate the desired topological physics. By introducing ferromagnetism into QSH state, we extend the mechanism to QAH state with a boosted gap. The QSH and QAH states can be achieved when Fermi level is at integer filling only for honeycomb lattice, but at certain fractional filling for other lattices. We conclude with a brief discussion on the possible material venues for such mechanism.
