Anomalous retardation of relativistic plasmons: Microwave response of a gated two-dimensional electron system

Abstract

We investigate the microwave response of a gated two-dimensional electron system (2DES) loaded by an external on-chip resonator. We find the system response to be dominated by the excitation of relativistic plasmons. These plasmons exhibit anomalously strong coupling to the photon mode of the resonator, which manifests itself in a drastic reduction of the plasma resonant frequency and linewidth. We develop an analytical approach to explain the observed phenomenon of strong interaction of 2D plasma with light. The theory turned out to be in good agreement with the experiment.