%0 Journal Article
%T Hidden-Symmetry-Protected Topological Semimetals on a Square Lattice
%A Jing-Min Hou
%J Physics
%D 2012
%I arXiv
%R 10.1103/PhysRevLett.111.130403
%X 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.
%U http://arxiv.org/abs/1212.4202v3