Topological Phase Transitions and Quantum Hall Effect in the Graphene Family

TL;DR

This paper explores how topological phase transitions and the quantum Hall effect coexist in graphene family materials, revealing their impact on Hall conductivity and potential for optoelectronic applications.

Contribution

It demonstrates the interplay of photo-induced topological phases and quantum Hall effects in graphene family materials, linking spectral responses to topological features.

Findings

Spectral response of longitudinal conductivity signals phase transitions.

Transverse conductivity encodes band topology information.

Resonant peaks relate to Dirac cones in the material.

Abstract

Monolayer staggered materials of the graphene family present intrinsic spin-orbit coupling and can be driven through several topological phase transitions using external circularly polarized lasers, and static electric or magnetic fields. We show how topological features arising from photo-induced phase transitions and the quantum Hall effect coexist in these materials, and simultaneously impact their Hall conductivity through their corresponding charge Chern numbers. We also show that the spectral response of the longitudinal conductivity contains signatures about the various phase transition boundaries, that the transverse conductivity encodes information about the topology of the band structure, and that both present resonant peaks which can be unequivocally associated to one of the four inequivalent Dirac cones present in these materials. This complex optoelectronic response can be probed with straightforward Faraday rotation experiments, allowing the study of the crossroads between quantum Hall physics, spintronics, and valleytronics.