All-optical band engineering of gapped Dirac materials

TL;DR

This paper theoretically explores how strong off-resonant electromagnetic fields can be used to control the electronic band structure and spin-valley properties of gapped Dirac materials, enabling tunable optoelectronic functionalities.

Contribution

It introduces a method to manipulate band gaps and spin-orbit splitting in gapped Dirac materials using polarized dressing fields, revealing polarization-dependent effects.

Findings

Linearly polarized fields decrease the band gap, potentially closing it.

Circularly polarized fields can increase or decrease band gaps and break valley symmetry.

Dressing fields enable control over spin and valley degrees of freedom.

Abstract

We demonstrate theoretically that the interaction of electrons in gapped Dirac materials (gapped graphene and transition-metal dichalchogenide monolayers) with a strong off-resonant electromagnetic field (dressing field) substantially renormalizes the band gaps and the spin-orbit splitting. Moreover, the renormalized electronic parameters drastically depend on the field polarization. Namely, a linearly polarized dressing field always decreases the band gap (and, particularly, can turn the gap into zero), whereas a circularly polarized field breaks the equivalence of valleys in different points of the Brillouin zone and can both increase and decrease corresponding band gaps. As a consequence, the dressing field can serve as an effective tool to control spin and valley properties of the materials and be potentially exploited in optoelectronic applications.