Light-induced large and tunable valley-selective Hall effect in a centrosymmetric system

TL;DR

This paper demonstrates that a large, tunable valley-selective Hall effect can be induced in centrosymmetric systems like graphene using bicircular light, enabling control over valley polarization with significant conductivity improvements.

Contribution

It introduces a method to realize a large, tunable valley Hall effect in centrosymmetric systems through light-induced symmetry breaking, surpassing previous noncentrosymmetric approaches.

Findings

Hall conductivity is two orders of magnitude larger than in noncentrosymmetric systems.

Valley switching can be achieved by tuning phase difference in bicircular light.

The effect enables control of valley polarization in centrosymmetric materials.

Abstract

We propose that a large and tunable valley-selective Hall effect can be realized in a centrosymmetric system via light-induced breaking of inversion and time-reversal symmetries. This is demonstrated in graphene driven by bicircularly polarized light, which consists of a linear combination of left- and right-handed circularly polarized light with different frequencies. We also show that our Hall conductivity is two orders of magnitude larger than the maximum value obtained in noncentrosymmetric systems, and that the main valley can be switched by tuning a phase difference between the left- and right-handed circularly polarized light. Our results will enable us to generate and control the valley-selective Hall effect in centrosymmetric systems.