Optical dressing of the electronic response of twodimensional semiconductors in quantum and classical descriptions of cavity electrodynamics
Abstract
We study quantum effects of the vacuum lightmatter interaction in materials embedded in optical cavities. We focus on the electronic response of a twodimensional semiconductor placed inside a planar cavity. By using a diagrammatic expansion of the electronphoton interaction, we describe signatures of lightmatter hybridization characterized by large asymmetric shifts of the spectral weight at resonant frequencies. We follow the evolution of the light dressing from the cavity to the freespace limit. In the cavity limit, lightmatter hybridization results in a modification of the optical gap with sizable spectral weight appearing below the bare gap edge. In the limit of large cavities, we find a residual redistribution of spectral weight which becomes independent of the distance between the two mirrors. We show that the photon dressing of the electronic response can be fully explained by using a classical description of light. The classical description is found to hold up to a strong coupling regime of the lightmatter interaction highlighted by the large modification of the photon spectra with respect to the empty cavity. We show that, despite the strong coupling, quantum corrections are negligibly small and weakly dependent on the cavity confinement. As a consequence, in contrast to the optical gap, the singleparticle electronic band gap is not sensibly modified by strong coupling. Our results show that quantum corrections are dominated by offresonant photon modes at high energy. As such, cavity confinement can hardly be seen as a knob to control the quantum effects of the lightmatter interaction in vacuum.
 Publication:

Physical Review B
 Pub Date:
 December 2021
 DOI:
 10.1103/PhysRevB.104.235120
 arXiv:
 arXiv:2106.06370
 Bibcode:
 2021PhRvB.104w5120A
 Keywords:

 Condensed Matter  Mesoscale and Nanoscale Physics;
 Quantum Physics
 EPrint:
 14 pages, 9 figures