Weyl Points of the Entanglement Spectrum for Topological Insulators from First Principles*

As for the three dimensional topological insulators, the parity of the Weyl points of an entanglement spectrum in the half of the Brillouin zone characterizes the strong topological insulator (STI) phase from the weak one (WTI phase)[1]. The STI/WTI phase corresponds to the odd/even parity. Without using any symmetry such as spatial inversion, one can easily specify the Weyl points by the section Chern number of the entanglement Hamiltonians. We apply this characterization method to realistic topological insulator materials using the first principle calculations.
[1] H. Araki, T. Fukui, and Y. Hatsugai, PRB 96, 165139 (2017)