Symmetry transformation of nonlinear optical current of tilted Weyl nodes and application to ferromagnetic MnBi2Te4

TL;DR

This paper develops a theory on how nonlinear optical conductivity in tilted Weyl nodes transforms under symmetry operations and proposes ferromagnetic MnBi2Te4 as a tunable terahertz optical device leveraging these properties.

Contribution

It introduces a theoretical framework for symmetry transformations of nonlinear optical responses in tilted Weyl semimetals and applies it to design a magnetoelectric terahertz device using MnBi2Te4.

Findings

Transformation rules for optical conductivity under tilt and chirality reversal.

Proposal of MnBi2Te4 as a magnetoelectric terahertz device.

Potential for topological Weyl semimetal-based nonlinear optical devices.

Abstract

A Weyl node is characterized by its chirality and tilt. We develop a theory of how $n$th-order nonlinear optical conductivity behaves under transformations of anisotropic tensor and tilt, which clarify how chirality-dependent and -independent parts of optical conductivity transform under the reversal of tilt and chirality. Built on this theory, we propose ferromagnetic $\rm MnBi_{2}Te_{4}$ as a magnetoelectrically regulated, terahertz optical device, by magnetoelectrically switching the chirality-dependent and -independent dc photocurrents. These results are useful for creating nonlinear optical devices based on topological Weyl semimetals.