Photon-mediated electronic correlation effects in irradiated two-dimensional Dirac systems

TL;DR

This paper introduces a novel approach to study photon-mediated electronic correlations in irradiated 2D Dirac systems, revealing topological band structures and degeneracy lifting effects without relying on Floquet theory.

Contribution

It presents a unitary transformation method to analyze photon-mediated interactions, offering new insights into topological phases in light-driven Dirac materials.

Findings

Photon-mediated interactions induce topological band structures.

Degeneracy of Dirac cones can be lifted by effective electron-electron interactions.

Method applicable to various light-driven Dirac systems.

Abstract

Periodically driven systems can host many interesting and intriguing phenomena. The irradiated two-dimensional Dirac systems, driven by circularly polarized light, are the most attractive thanks to intuitive physical view of the absorption and emission of photon near Dirac cones. Here, we assume that the light is incident in the two-dimensional plane, and choose to treat the light-driven Dirac systems by making a unitary transformation to capture the photon-mediated electronic correlation effects, instead of using usual Floquet theory. In this approach, the electron-photon interaction terms can be cancelled out and the resultant effective electron-electron interactions can produce important effects. These effective interactions will produce a topological band structure in the case of 2D Fermion system with one Dirac cone, and can lift the energy degeneracy of the Dirac cones for graphene. This method can be applicable to similar light-driven Dirac systems to investigate photon-mediated electronic effects in them.