Resonant plasmon-phonon coupling and its role in magneto-thermoelectricity in bismuth

TL;DR

This paper investigates how resonant coupling between plasmons and phonons in bismuth influences magneto-thermoelectric effects, revealing a novel energy transfer mechanism that may explain the large Nernst effect.

Contribution

It introduces a diagrammatic derivation of plasmon-phonon interaction showing a resonant structure affecting thermoelectric properties in bismuth.

Findings

Resonant plasmon-phonon coupling significantly alters phonon-drag.

The mechanism may explain the large Nernst effect in bismuth.

Resonance occurs when plasmon and phonon velocities are comparable.

Abstract

Using diagrammatic methods we derive an effective interaction between a low energy collective movement of fermionic liquid (acoustic plasmon) and acoustic phonon. We show that the coupling between the plasmon and the lattice has a very non-trivial, resonant structure. When real and imaginary parts of the acoustic plasmon's velocity are of the same order as the phonon's velocity, the resonance qualitatively changes the nature of phonon-drag. In the following we study how magneto-thermoelectric properties are affected. Our result suggests that the novel mechanism of energy transfer between electron liquid and crystal lattice can be behind the huge Nernst effect in bismuth.