Near-field heat transfer between disordered conductors

TL;DR

This paper investigates how disorder in conductors affects near-field heat transfer, revealing a transition from a T^4 to a T^3 temperature dependence due to diffusive electronic density fluctuations.

Contribution

It demonstrates that electron scattering in disordered metals qualitatively alters near-field heat transfer laws, enhancing heat flux at low temperatures.

Findings

Heat flux in clean metals follows T^4 law.

Disordered conductors exhibit a T^3 dependence.

Disorder significantly enhances near-field heat transfer.

Abstract

We study heat transfer mediated by near-field fluctuations of the electromagnetic field. In case of metals the latter are dominated by Coulomb interactions between thermal fluctuations of electronic density. We show that an elastic scattering of electrons, leading to diffusive propagation of density fluctuations, results in a qualitative change of the radiation law. While the heat flux between clean metals follows the Stefan-Boltzmann-like $T^4$ dependence, the heat exchange between disordered conductors is significantly enhanced and scales as $T^3$ at low temperatures.