Dirac semimetals $A_3Bi$ ($A$=Na,K,Rb) as $Z_2$ Weyl semimetals

E. V. Gorbar; V. A. Miransky; I. A. Shovkovy; P. O. Sukhachov

doi:10.1103/physrevb.91.121101

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arXiv · 1412.5194

Dirac semimetals $A_3Bi$ ($A$=Na,K,Rb) as $Z_2$ Weyl semimetals

E. V. Gorbar·V. A. Miransky·I. A. Shovkovy·P. O. Sukhachov

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Abstract

We demonstrate that the physical reason for the nontrivial topological properties of Dirac semimetals $A_3 Bi$ (A=Na,K,Rb) is connected with a discrete symmetry of the low-energy effective Hamiltonian. By making use of this discrete symmetry, we argue that all electron states can be split into two separate sectors of the theory. Each sector describes a Weyl semimetal with a pair of Weyl nodes and broken time-reversal symmetry. The latter symmetry is not broken in the complete theory because the time-reversal transformation interchanges states from different sectors. Our findings are supported by explicit calculations of the Berry curvature. In each sector, the field lines of the curvature reveal a pair of monopoles of the Berry flux at the positions of Weyl nodes. The $Z_2$ Weyl semimetal nature is also confirmed by the existence of pairs of surface Fermi arcs, which originate from different sectors of the theory.

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BibTeX RIS

E. V. Gorbar, V. A. Miransky, I. A. Shovkovy, P. O. Sukhachov. 2015-03-03. Dirac semimetals $A_3Bi$ ($A$=Na,K,Rb) as $Z_2$ Weyl semimetals. https://doi.org/10.1103/physrevb.91.121101

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