Manifestation of chiral magnetic current in Floquet-Weyl semimetals

TL;DR

This paper demonstrates how to induce and sustain a chiral magnetic current in Floquet-Weyl semimetals by using dynamical transitions and dissipation, overcoming previous no-go theorems in equilibrium systems.

Contribution

It introduces a method to realize the chiral magnetic effect in condensed matter by driving insulators with time-periodic potentials and coupling to a heat bath.

Findings

Floquet-Weyl phase with Fermi-Dirac distribution emerges.

Non-vanishing chiral magnetic current is supported in steady state.

Dynamical transitions enable breaking of no-go theorem constraints.

Abstract

Materials that can host macroscopic persistent current are important because they are useful for energy storage. However, there are very few examples of such materials in nature. Superconductors are known as an example in which flow of supercurrent can persist up to 100,000 years. The chiral magnetic current is possibly the second example predicted by the chiral magnetic effect. It was proposed to be realized in recently discovered Weyl semimetals. However, a no-go theorem negates the chiral magnetic effect and shows that the chiral magnetic current is generally absent in any equilibrium condensed-matter system. Here we show how to break the no-go theorem by resorting to dynamical transitions in time-frequency space. By driving an insulator using a time-periodic potential and coupling it to a phonon heat bath that provides suitable dissipation, we show that a Floquet-Weyl semi-metallic phase with Fermi-Dirac-like distribution emerges. Furthermore, we show that even in the presence of a static magnetic field, the resulting steady Floquet-Weyl semimetal supports non-vanishing chiral magnetic current. Our dynamical model provides a systematic way to fully realize the chiral magnetic effect in condensed matter systems.