Universal self-amplification channel for surface plasma waves
Hai-Yao Deng, Katsunori Wakabayashi, and Chi-Hang Lam
Phys. Rev. B 95, 045428 – Published 30 January 2017
https://doi.org/10.1103/PhysRevB.95.045428

ABSTRACT
We present a theory of surface plasma waves (SPWs) in metals with arbitrary electronic collision rate. We show that there exists a universal intrinsic amplification channel for these waves, subsequent to the interplay between ballistic motions and the metal surface. We evaluate the corresponding amplification rate, which turns out to be a sizable fraction of the SPW frequency. We also find that the value of the amplification rate depends on surface scattering properties, in contrast with the conventional theory.