Magnetoplasmon Fano resonance in Bose-Fermi mixtures

TL;DR

This paper theoretically analyzes magnetoplasmon Fano resonance in a hybrid Bose-Fermi system, revealing a double-resonance spectrum with tunable features influenced by magnetic field, exciton density, and impurity scattering, offering insights for experimental detection.

Contribution

It introduces a theoretical model showing how Fano resonance profiles emerge in a coupled electron-exciton system and how their shapes and positions depend on system parameters.

Findings

The absorption spectrum shows a double-resonance with Fano profile.

The excitonic peak is extremely narrow compared to the magnetoplasmon peak.

Resonance shapes and positions depend on magnetic field, exciton density, and impurity scattering.

Abstract

We investigate theoretically the magnetoplasmon (cyclotron) resonance in a hybrid system consisting of spatially separated two-dimensional layers of electron and dipolar exciton gases coupled via the Coulomb forces. We study the dynamics of this system under the action of weak alternating external electromagnetic field in the presence of uniform magnetic field, perpendicular to the layers. We reveal that the electromagnetic power absorption exhibits a double-resonance spectrum. We show that the first resonance is associated with the conventional well-studied magnetoplasmon excitations of the electron gas and it has a standard Lorentzian shape, whereas the second resonance is a peculiarity attributed to the Bose-condensed exciton gas. Further, we explicitly demonstrate that the spectrum of the system exhibits an asymmetric Fano-type profile, where the excitonic peak is extremely narrow in comparison with the magnetoplasmon one. We show that the shape of the resonance and the position of the peaks depends on the magnitude of the applied magnetic field, exciton condensate density and exciton-impurity scattering time. In particular, the Fano profile turns into a Lorentzian shape with decreasing exciton-impurity scattering time and the position of the plasmon-associated resonance is mainly sensitive and determined by the magnetic field strength, whereas the exciton-condensate peak position is determined by exciton condensate density. It opens the experimental possibility to determine the latter quantity in cyclotron resonance experiment.