Surface Fermi arcs in $Z_2$ Weyl semimetals $A_3 Bi$ (A=Na, K, Rb)

TL;DR

This paper investigates the properties of surface Fermi arc states in $Z_2$ Weyl semimetals $A_3 Bi$ (A=Na, K, Rb) using a continuum model, revealing symmetry classifications and different arc types.

Contribution

It introduces a classification of Fermi arc states based on ud-parity symmetry and analyzes how symmetry breaking affects their structure.

Findings

Fermi arcs come in mirror symmetric pairs due to symmetry.

Identifies two qualitatively different types of Fermi arcs.

Some arcs connect disconnected bulk Fermi surface sheets, others connect points within the same sheet.

Abstract

The surface Fermi arc states in $Z_2$ Weyl semimetals $A_3 Bi$ (A=Na, K, Rb) are studied by employing a continuum low-energy effective model. It is shown that the surface Fermi arc states can be classified with respect to the ud-parity symmetry. Because of the symmetry, the arcs come in mirror symmetric pairs. The effects of symmetry breaking terms on the structure of the Fermi arcs are also studied. Among other results, we find at least two qualitatively different types of the surface Fermi arcs. The arcs of the first type link disconnected sheets of the bulk Fermi surface, while arcs of the second type link different points of the same bulk Fermi surface sheet.