Topological Weyl Semi-metal from a Lattice Model

TL;DR

This paper introduces a three-dimensional lattice model that exhibits a Weyl semi-metallic phase, characterized by topologically protected surface states and Fermi arcs, bridging quantum Hall and normal insulators.

Contribution

It presents a novel lattice model of Weyl semi-metal derived from coupled quantum Hall layers, analyzing its topological surface states and phase transitions.

Findings

Identification of Weyl semi-metal phase between quantum Hall and normal insulators

Observation of Fermi arcs and surface states in the model

Topological analysis of phase evolution

Abstract

We define and study a three dimensional lattice model which displays a Weyl semi-metallic phase. This model consists of coupled layers of quantum (anomalous) Hall insulators. The Weyl semi-metallic phase appears between a resulting quantum Hall insulating phase and a normal insulating phase. Weyl fermions in this Weyl semi-metal, similar to Dirac fermions in graphene, have their lattice pseudo-spin locked to their momenta. We investigate surface states and Fermi arcs, and their evolution for different phases, by exactly diagonalizing the lattice model as well as by analyzing their topological origins.