Novel relativistic plasma excitations in a gated two-dimensional electron system

TL;DR

This paper reports the discovery of relativistic plasma excitations in a gated 2D electron system, which exhibit unique magnetic and geometric dependencies and remain stable up to room temperature, opening new application possibilities.

Contribution

It introduces the observation of relativistic plasmons in a 2DES with high conductivity, demonstrating their unusual behavior and potential for room-temperature microwave and terahertz technologies.

Findings

Weakly damped plasma waves are excited in the relativistic regime.

Plasma excitation properties depend unusually on magnetic field and gate geometry.

Relativistic plasmons persist at temperatures up to 300 K.

Abstract

The microwave response of a two-dimensional electron system (2DES) covered by a conducting top gate is investigated in the relativistic regime for which the 2D conductivity $\sigma_{2 \rm{D}} > c/2\pi$. Weakly damped plasma waves are excited in the gated region of the 2DES. The frequency and amplitude of the resulting plasma excitations show a very unusual dependence on the magnetic field, conductivity, gate geometry and separation from the 2DES. We show that such relativistic plasmons survive for temperatures up to 300 K, allowing for new room-temperature microwave and terahertz applications.