Scaling of the chiral magnetic effect in quantum diffusive Weyl semimetals

TL;DR

This paper studies how short-range disorder affects the chiral magnetic effect in Weyl semimetals, revealing that disorder suppresses the effect and that localization phenomena influence its observability.

Contribution

It provides a detailed analysis of disorder effects on the CME in Weyl semimetals, including the roles of Drude correction and Cooperon contributions, highlighting the impact of localization.

Findings

Drude correction renormalizes the CME coefficient to a finite, size-independent value.

Cooperon contribution to CME is governed by quartic momentum terms.

Localization effects influence the observability of the CME in disordered systems.

Abstract

We investigate the effect of short-range spin-independent disorder on the chiral magnetic effect (CME) in Weyl semimetals. Based on a minimum two-band model, the disorder effect is examined in the quantum diffusion limit by including the Drude correction and the correction due to the Cooperon channel. It is shown that the Drude correction renormalizes the CME coefficient by a factor to a finite value that is independent of the system size. Furthemore, due to an additional momentum expansion involved in deriving the CME coefficient, the contribution of Cooperon to the CME coefficient is governed by the quartic momentum term. As a result, in contrast to the weak localization and weak anti-localization effects observed in the measurement of conductivity of Dirac fermions, we find that in the limit of zero magnetic field, the CME coefficients of finite systems manifest the same scaling of localization even in three dimension. Our results indicate that while the chiral magnetic current due to slowly oscillating magnetic fields can exist in clean systems, its observability will be limited by suppression due to short-range disorder in condensed matters.