Evidence of Floquet electronic steady states in graphene under continuous-wave mid-infrared irradiation

TL;DR

This study demonstrates the existence of long-lived Floquet electronic steady states in graphene under continuous-wave mid-infrared irradiation, revealing new possibilities for Floquet engineering of non-equilibrium phases.

Contribution

It provides experimental evidence of stable Floquet states in graphene induced by CW laser, a regime previously unexplored with continuous illumination.

Findings

Detection of non-equilibrium steady states in graphene.

Identification of Floquet phase signatures through transport measurements.

Long-lived electronic populations stabilized by laser and phonon interactions.

Abstract

Light-induced phenomena in materials can exhibit exotic behavior that extends beyond equilibrium properties, offering new avenues for understanding and controlling electronic phases. So far, non-equilibrium phenomena in solids have been predominantly explored using femtosecond laser pulses, which generate transient, ultra-fast dynamics. Here, we investigate the steady non-equilibrium regime in graphene induced by a continuous-wave (CW) mid-infrared laser. Our transport measurements reveal signatures of a long-lived Floquet phase, where a non-equilibrium electronic population is stabilized by the interplay between coherent photoexcitation and incoherent phonon cooling. The observation of non-equilibrium steady states using CW lasers opens a new regime for low-temperature Floquet phenomena, paving the way toward Floquet engineering of steady-state phases of matter.