Floquet chiral magnetic effect

TL;DR

This paper demonstrates the realization of a Weyl fermion and the chiral magnetic effect in a periodically driven 3D lattice system, providing a topological classification of Floquet operators and predicting new surface states in Floquet topological phases.

Contribution

It introduces a topological classification of Floquet unitary operators and shows how Weyl fermions and chiral magnetic effects can emerge in driven lattice systems.

Findings

Realization of Weyl fermions in Floquet systems

Topological classification of Floquet operators across symmetry classes

Prediction of gapless surface states in Floquet topological insulators

Abstract

A single Weyl fermion, which is prohibited in static lattice systems by the Nielsen-Ninomiya theorem, is shown to be realized in a periodically driven three-dimensional lattice system with a topologically nontrivial Floquet unitary operator, manifesting the chiral magnetic effect. We give a topological classification of Floquet unitary operators in the Altland-Zirnbauer symmetry classes for all dimensions, and use it to predict that all gapless surface states of topological insulators and superconductors can emerge in bulk quasienergy spectra in Floquet systems.