Large circular photogalvanic effect in the noncentrosymmetric magnetic Weyl semimetal CeAlSi

TL;DR

This study reveals a large circular photogalvanic effect in CeAlSi, a magnetic Weyl semimetal, with significant injection currents and tunability via strain, highlighting its potential for advanced photogalvanic devices.

Contribution

First-principles calculations uncover a substantial injection current in CeAlSi and demonstrate strain-induced enhancement, advancing understanding of light-matter interactions in magnetic Weyl semimetals.

Findings

Injection current of 4 mA/V$^2$ in CeAlSi

64% increase in photocurrent with 5% uniaxial strain

Potential for novel photogalvanic applications

Abstract

The recent discovery of the Weyl semimetal CeAlSi with simultaneous breaking of inversion and time-reversal symmetries has opened up new avenues for research into the interaction between light and topologically protected bands. In this work, we present a comprehensive examination of the shift current and injection current responsible for the circular photogalvanic effect in CeAlSi using first-principles calculations. Our investigation identifies a significant injection current of 4 mA/V$^2$ over a broad range in the near-infrared region of the electromagnetic spectrum, exceeding previously reported findings. In addition, we explored several externally controllable parameters to further enhance the photocurrent. A substantial boost in the injection current is observed when applying uniaxial strain along the $c$ axis of the crystal: a 5% strain results in a remarkable 64% increment. The exceptional photocurrent response in CeAlSi suggests that magnetic non-centrosymmetric Weyl semimetals may provide promising opportunities for novel photogalvanic applications.