Quantum Effects of Impurities and Lattice Defects in Topological Semimetals

TL;DR

This paper investigates how impurities and lattice defects influence the electronic and electrodynamic properties of topological semimetals, specifically Weyl semimetals, revealing the robustness and sensitivity of their topological features to disorder.

Contribution

It provides a detailed analysis of the effects of various types of disorder on Weyl semimetals' electronic structure and electrodynamics, advancing understanding of their robustness.

Findings

Impurities modify the electronic band structure of Weyl semimetals.

Disorder affects the topological protection of band-touching points.

Lattice defects influence the electrodynamic response of the material.

Abstract

Topological semimetals are a class of novel three-dimensional (3D) electronic phases that feature topologically protected conical band-touchings at the Fermi level. These band-touching points are monopoles of Berry curvature in momentum space and effectively realize (3+1)-dimensional Weyl fermions as emergent quasiparticles. Such features are robust to perturbations but not completely insensitive to them. In this thesis, we explore the yet fertile ground of disordered Weyl semimetals (WSMs), most notably by analysing the effects of on-site random fields, random smooth potential regions, point-like scalar impurities, and lattice point-defects in their electronic structure and electrodynamic properties.