# Dynamic chiral magnetic effect and anisotropic natural optical activity of tilted Weyl semimetals

## TL;DR

This paper investigates the anisotropic optical activity and dynamic chiral magnetic conductivity in tilted Weyl semimetals, revealing their dependence on tilt direction and frequency, with implications for experimental detection of topological effects.

## Contribution

It provides analytical expressions for DCMC in tilted WSMs, demonstrating anisotropic optical activity and identifying signatures distinguishing type-I and type-II Weyl semimetals.

## Key findings

- Optical activity exhibits anisotropic behavior aligned with tilt direction.
- DCMC follows a universal 1/ω² decay at high frequencies.
- Sharp peaks in DCMC at tilt-dependent chemical potentials at low frequencies.

## Abstract

We study the dynamic chiral magnetic conductivity (DCMC) and natural optical activity in an inversion-broken tilted Weyl semimetal (WSM). Starting from the Kubo formula, we derive the analytical expressions for the DCMC for two different directions of the incident electromagnetic wave. We show that the angle of rotation of the plane of polarization of the transmitted wave exhibits remarkable anisotropic behavior and is larger along the tilt direction. This striking anisotropy of DCMC which results in anisotropic optical activity and rotary power, can be experimentally observed as a topological magneto-electric effect of inversion-broken tilted WSMs. Finally, using the low energy Hamiltonian, we show that the DCMC follows the universal $\frac{1}{\omega^2}$ decay in the high frequency regime. In the low frequency regime, however, the DCMC shows sharp peaks at the tilt dependent effective chemical potentials of the left-handed and right-handed Weyl points. This can serve as a signature to distinguish between the type-I and type-II Weyl semimetals.