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arXiv · 1605.08291

$Z_2$ antiferromagnetic topological insulators with broken $C_4$ symmetry

Frédéric Bègue·Pierre Pujol·Revaz Ramazashvili
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Abstract

A two-dimensional topological insulator may arise in a centrosymmetric commensurate Néel antiferromagnet (AF), where staggered magnetization breaks both the elementary translation and time reversal, but retains their product as a symmetry. Fang et al.[Phys. Rev. B 88, 085406 (2013)] proposed an expression for a $Z_2$ topological invariant to characterize such systems. Here, we show that this expression does not allow to detect all the existing phases if a certain lattice symmetry is lacking. We implement numerical techniques to diagnose topological phases of a toy Hamiltonian, and verify our results by computing the Chern numbers of degenerate bands, and also by explicitly constructing the edge states, thus illustrating the efficiency of the method.

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Frédéric Bègue, Pierre Pujol, Revaz Ramazashvili. 2016-05-26. $Z_2$ antiferromagnetic topological insulators with broken $C_4$ symmetry. https://doi.org/10.1016/j.physleta.2017.02.003

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