Enhanced photoenergy harvesting and extreme Thomson effect in hydrodynamic electronic systems

TL;DR

This paper explores how electron-electron interactions in hydrodynamic electronic systems dramatically alter thermoelectric properties, leading to enhanced efficiency and novel effects like an extreme Thomson effect, especially in graphene.

Contribution

It reveals new thermoelectric phenomena arising from hydrodynamic electron behavior, including increased efficiency and anomalous Thomson effects, with detailed analysis in graphene.

Findings

80-fold increase in thermoelectric efficiency

Dramatic changes in temperature profiles

Large Thomson effect in hydrodynamic regime

Abstract

The thermoelectric (TE) properties of a material are dramatically altered when electron-electron interactions become the dominant scattering mechanism. In the degenerate hydrodynamic regime, the thermal conductivity is reduced and becomes a {\it decreasing} function of the electronic temperature, due to a violation of the Wiedemann-Franz (WF) law. We here show how this peculiar temperature dependence gives rise to new striking TE phenomena. These include an 80-fold increase in TE efficiency compared to the WF regime, dramatic qualitative changes in the steady state temperature profile, and an anomalously large Thomson effect. In graphene, which we pay special attention to here, these effects are further amplified due to a doubling of the thermopower.