Two-dimensional topological semimetal state in a nanopatterned semiconductor system

TL;DR

This paper proposes a method to create a two-dimensional topological semimetal in a semiconductor lattice, driven by an in-plane magnetic field, with potential detection through edge conductance measurements.

Contribution

It introduces a novel approach to realize a 2D topological semimetal in semiconductor systems using nanopatterned lattices and magnetic field tuning.

Findings

Topological semimetal characterized by band touching points with quantized Berry flux.

Quantum phase transition from topological insulator to semimetal at ~4T magnetic field.

Edge conductance anomalies as a signature of the topological phase transition.

Abstract

We propose the creation of a two-dimensional topological semimetal in a semiconductor artificial lattice with triangular symmetry. An in-plane magnetic field drives a quantum phase transition between the topological insulating and topological semimetal phases. The topological semimetal is characterized by robust band touching points which carry quantized Berry flux and edge states which terminate at the band touching points. The topological phase transition is predicted to occur at magnetic fields $\sim 4\text{T}$ in high mobility GaAs artificial lattices, and can be detected via the anomalous behaviour of the edge conductance.