High-harmonic spectroscopy of light-driven nonlinear anisotropic anomalous Hall effect in a Weyl semimetal

TL;DR

This paper demonstrates that high-harmonic spectroscopy can probe the topological Berry curvature in Weyl semimetals, revealing a nonlinear anisotropic anomalous Hall effect driven by laser-induced electron dynamics.

Contribution

It introduces a novel method to detect Berry curvature topology in Weyl semimetals via high-harmonic generation measurements.

Findings

Berry curvature controls anomalous harmonic generation

Polarization of emitted harmonics reveals topological properties

Laser-driven dynamics induce ultrafast nonlinear Hall effects

Abstract

Weyl semimetals are promising quantum materials that offer unique topological properties. Lately, it has been shown that laser-driven electron dynamics have characteristic signatures in two-dimensional and three-dimensional Dirac semimetals. The transition from Dirac to Weyl semimetal requires the breaking of either inversion or time-reversal symmetry. The present work shows that the laser-driven electron dynamics in a Weyl semimetal with broken time-reversal symmetry has intriguing features in its high-harmonic spectrum. It is found that the parity and magnitude of the non-zero Berry curvature's components control the direction and strength of the anomalous current, which leads to the generation of the anomalous odd harmonics. We demonstrate that the non-trivial topology of the Berry curvature in time-reversal symmetry broken quantum materials can be probed by measuring the polarisation of the emitted anomalous odd harmonics. Our findings unequivocally illustrate that laser-driven electron dynamics leads to the generation of nonlinear anisotropic anomalous Hall effect in time-reversal symmetry broken quantum materials on an ultrafast timescale.