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arXiv · 1710.06453

Coupling effect of topological states and Chern insulators in two-dimensional triangular lattices

Jiayong Zhang·Bao Zhao·Yang Xue·Tong Zhou·Zhongqin Yang
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Abstract

We investigate topological states of two-dimensional (2D) triangular lattices with multi-orbitals. Tight-binding model calculations of a 2D triangular lattice based on $\emph{p}_{x}$ and \emph{p}_{y} orbitals exhibit very interesting doubly degenerate energy points at different positions ($Γ$ and K/K$^{\prime}$) in momentum space, with quadratic non-Dirac and linear Dirac band dispersions, respectively. Counterintuitively, the system shows a global topologically trivial rather than nontrivial state with consideration of spin-orbit coupling due to the "destructive interference effect" between the topological states at the $Γ$ and K/K$^{\prime}$ points. The topologically nontrivial state can emerge by introducing another set of triangular lattices to the system (bitriangular lattices) due to the breakdown of the interference effect. With first-principles calculations, we predict an intrinsic Chern insulating behavior (quantum anomalous Hall effect) in a family of 2D triangular lattice metal-organic framework of Co(C$_{21}$N$_{3}$H$_{15}$) (TPyB-Co) from this scheme. Our results provide a different path and theoretical guidance for the search for and design of new 2D topological quantum materials.

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Jiayong Zhang, Bao Zhao, Yang Xue, Tong Zhou, Zhongqin Yang. 2018-03-28. Coupling effect of topological states and Chern insulators in two-dimensional triangular lattices. https://doi.org/10.1103/physrevb.97.125430

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