Helical Fermi arcs and surface states in time-reversal invariant Weyl semimetals

TL;DR

This paper investigates a zincblende lattice model of a time-reversal invariant Weyl semimetal, revealing unique helical surface states with velocity and spin locked to crystal symmetry axes, differing from topological insulator Dirac states.

Contribution

It introduces a specific lattice model exhibiting time-reversal invariant Weyl semimetal behavior and characterizes its distinctive helical surface states influenced by crystal symmetry.

Findings

Bulk hosts twelve helical Weyl nodes.

Surface states form a quasi-2D helical metal.

Surface state properties are locked to cubic symmetry axes.

Abstract

Weyl semimetals are gapless three-dimensional topological materials where two bands touch at even number of points in the Brillouin zone. In this work we study a zincblende lattice model realizing a time-reversal invariant Weyl semimetal. The bulk dynamics is decribed by twelve helical Weyl nodes. Surface states form a peculiar quasi two-dimensional helical metal fundamentally different from the Dirac form typical for topological insulators. Allowed direction of velocity and spin of low-energy surface excitations are locked to the cubic symmetry axes. The studied system illustrates general properties of surface states in systems with common crystal symmetries.