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arXiv · 1212.4202

Hidden-Symmetry-Protected Topological Semimetals on a Square Lattice

Jing-Min Hou
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Abstract

We study a two-dimensional fermionic square lattice, which supports the existence of two-dimensional Weyl semimetal, quantum anomalous Hall effect, and $2\pi$-flux topological semimetal in different parameter ranges. We show that the band degenerate points of the two-dimensional Weyl semimetal and $2\pi$-flux topological semimetal are protected by two distinct novel hidden symmetries, which both corresponds to antiunitary composite operations. When these hidden symmetries are broken, a gap opens between the conduction and valence bands, turning the system into a insulator. With appropriate parameters, a quantum anomalous Hall effect emerges. The degenerate point at the boundary between the quantum anomalous Hall insulator and trivial band insulator is also protected by the hidden symmetry.

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Jing-Min Hou. 2012-12-18. Hidden-Symmetry-Protected Topological Semimetals on a Square Lattice. https://doi.org/10.1103/physrevlett.111.130403

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