Metallic electro-optic effects in topological chiral crystals

TL;DR

This study uncovers significant metallic electro-optic effects in topological chiral crystals, driven by Berry curvature and magnetic moments, with potential for experimental observation in specific materials like BeAu.

Contribution

It reveals nonzero Berry curvature dipoles in space group 198 crystals and demonstrates accessible magnetoelectric electro-optic effects in BeAu, expanding understanding of topological material responses.

Findings

Nonzero Berry curvature dipole in SG198 materials

Magnetoelectric EO effects are experimentally feasible in BeAu

Electro-optic responses linked to Berry curvature and magnetic moments

Abstract

Topological chiral crystals have emerged as a fertile material platform for investigating optical phenomena derived from the distinctive Fermi surface Berry curvature and orbital magnetic moment textures around multifold chiral band crossings pinned at the time-reversal invariant momenta. In this work, by means of tight-binding model and first principles based calculations, we investigate metallic electro-optic (EO) responses stemming from the Berry curvature and orbital magnetic moment of Bloch electrons across 37 materials belonging to space group 198 (SG198). Previously thought to vanish in SG198, our findings reveal a nonzero Berry curvature dipole attributed to the energetic misalignment between topologically charged point nodes of opposite chirality. Moreover, we find that the recently predicted magnetoelectric EO effects, which arise from the interplay between the Berry curvature and magnetic moment on the Fermi surface, are readily accessible in BeAu under experimentally feasible electric biases.