Negative longitudinal magnetoconductance at weak fields in Weyl semimetals

TL;DR

This paper demonstrates that Weyl semimetals can exhibit negative longitudinal magnetoconductance at weak magnetic fields due to Berry phase effects and intervalley scattering, challenging the conventional positive quadratic behavior as a chiral anomaly signature.

Contribution

The study analytically shows that negative magnetoconductance can occur in Weyl semimetals at weak fields, highlighting a new regime influenced by Berry phase and orbital magnetic moments.

Findings

Negative magnetoconductance occurs at weak fields.

Effect depends on intervalley scattering strength.

Challenging the traditional positive quadratic magnetoconductance signature.

Abstract

Weyl semimetals are topological materials that provide a condensed-matter realization of the chiral anomaly. A positive longitudinal magnetoconductance quadratic in magnetic field has been promoted as a diagnostic for this anomaly. By solving the Boltzmann equation analytically, we show that the magnetoconductance can become negative in the experimentally relevant semiclassical regime of weak magnetic fields. This effect is due to the simultaneous presence of the Berry phase and the orbital magnetic moment of carriers and occurs for sufficiently strong intervalley scattering.