Semiclassical theory of frequency dependent linear magneto-optical transport in Weyl semimetals

TL;DR

This paper develops a semiclassical Boltzmann theory to analyze frequency-dependent magneto-optical transport in Weyl semimetals, revealing how various factors influence the conductivity tensor and chiral anomaly signatures.

Contribution

It introduces a comprehensive semiclassical framework incorporating momentum-dependent relaxation and electromagnetic effects in Weyl semimetals.

Findings

Intervalley scattering causes sign reversal of LMOC in weak ac regime for untilted WSMs.

Orbital magnetic moment induces linear magnetic-field contributions to conductivity.

Tilt orientation significantly affects LMOC behavior, with negative LMOC arising intrinsically for parallel tilt.

Abstract

We develop a semiclassical Boltzmann theory for frequency-dependent magneto-optical transport in Weyl semimetals (WSMs), incorporating momentum-dependent relaxation via a scattering matrix approach. The interplay of orbital magnetic moment, Weyl cone tilt, intervalley scattering, and electromagnetic driving is analyzed to obtain the full conductivity tensor in the presence of a static magnetic field. For untilted WSMs with orbital magnetic moment, strong intervalley scattering in the weak ac regime induces a sign reversal of the longitudinal magneto-optical conductivity (LMOC), thereby suppressing the chiral anomaly. In contrast, in the strong ac regime, intervalley scattering fails to neutralize the chiral imbalance within a driving cycle, and no sign reversal is observed. Orbital magnetic moment induces linear magnetic-field contributions, while chiral anomaly yields quadratic response accompanied by expected angular profiles. Tilt direction and orientation strongly affect LMOC such as, transverse tilt gives symmetric non-monotonic behavior, whereas parallel tilt leads to asymmetric, nearly monotonic response. Notably, negative LMOC arises intrinsically for parallel tilt, but requires orbital magnetic moment for transverse tilt. These results highlight frequency-dependent conductivity as a sensitive probe of chiral relaxation in MHz-THz magneto-optical experiments.