Anomalous Transport Signatures in Weyl Semimetals with Point Defects

TL;DR

This paper theoretically investigates how point defects in Weyl semimetals affect their transport properties, revealing novel effects like oscillatory conductivity and a plateau optical response, which could enable defect-engineered quantum transport.

Contribution

It presents the first theoretical analysis of transport in Weyl semimetals with point defects, showing how vacancies induce localized states and modify low-energy transport phenomena.

Findings

Dilute vacancies create quasi-localized states near the nodal energy.

Transport exhibits oscillatory dc-conductivity with carrier density.

Optical response shows a plateau below the inter-band threshold.

Abstract

We present the first theoretical study of transport properties of Weyl semimetals with point defects. Focusing on a class of time-reversal symmetric Weyl lattice models, we show that dilute lattice vacancies induce a finite density of quasi-localized states at and near the nodal energy, causing strong modifications to the low-energy spectrum. This generates novel transport effects, namely (i) an oscillatory behaviour of the dc-conductivity with the charge carrier density in the absence of magnetic fields, and (ii) a plateau-shaped dissipative optical response for photon frequencies below the inter-band threshold, $E_{F}\!\lesssim\!\hbar\omega\!\lesssim\!2E_{F}$.Our results provide a path to engineer unconventional quantum transport effects in Weyl semimetals by means of common point defects.