Electron sound in metals

TL;DR

This study investigates electron sound in metals, combining experimental measurements of amplitude-phase relations in Ga crystals with a theoretical model of excitation in compensated metals, revealing significant amplitude amplification and superconducting transition effects.

Contribution

It provides the first experimental characterization of electron sound in Ga and a theoretical model for its excitation in compensated metals with diffusive interfaces.

Findings

Electron displacement amplitude exceeds elastic wave amplitude by two orders of magnitude.

Amplitude and phase changes at superconducting transition are independent of wave path.

Experimental and theoretical insights into electron sound propagation in metals.

Abstract

This paper is devoted to the investigation of electron sound -- oscillations of the electron distribution function coupled with elastic deformation and propagating with the Fermi velocity. The amplitude-phase relations characterizing the behavior of the electron sound in Ga single crystals are determined experimentally. A model problem of excitation of electron sound in a compensated metal with equivalent bands is solved for a finite sample with diffusive scattering of electrons at the interfaces. It was found that the displacement amplitude of the receiving interface is two orders of magnitude larger than the elastic amplitude of the wave due to electron pressure. It was established that the changes occurring in the amplitude and phase of the electron sound waves at a superconducting transition do not depend on the path traversed by the wave, i.e. they refer only to the behavior of the transformation coefficient.