Anomalous Transport Signatures in Weyl Semimetals with Point Defects

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, $E_F\text{\hspace{0.17em}⁣}\lesssim \text{\hspace{0.17em}⁣}\mathrm{\hslash }\omega \text{\hspace{0.17em}⁣}\lesssim \text{\hspace{0.17em}⁣}2E_F$.Our results provide a path to engineer unconventional quantum transport effects in Weyl semimetals by means of common point defects.