Terahertz instability of optical phonons interacting with plasmons in two-dimensional electron channels

Abstract

A terahertz (THz) instability can occur when optical phonons interact with drifting solid-state plasmas. We developed a theoretical model for the optical-phonon instability in two-dimensional electron channels. The paper derives the dispersion relation and analyzes the instability using parameters measured in InSb. As the calculations show, strong instability occurs around the longitudinal optical-phonon frequency, and both the growth rate and the unstable frequency band are larger for higher electron densities and lower drift velocities. The results demonstrate the potential of the optical-phonon instability for active THz devices.