Near field radiative heat transfer between two nonlocal dielectrics

TL;DR

This paper investigates near-field radiative heat transfer between two nonlocal dielectric planes using a Lorenz-Drude model, revealing deviations from classical laws at nanometer scales due to surface scattering effects.

Contribution

It introduces a nonlocal dielectric model incorporating surface scattering and boundary conditions, extending fluctuational electrodynamics to account for nonlocal effects in heat transfer.

Findings

Nonlocal effects cause deviations from the classical $1/d^2$ law at nanometer distances.

Surface scattering parameters significantly influence electromagnetic transmission.

Nonlocal modeling remains relevant beyond quantum effect regimes.

Abstract

We explore in the present work the near-field radiative heat transfer between two semi-infinite parallel nonlocal dielectric planes by means of fluctuational electrodynamics. We use atheory for the nonlocal dielectric permittivityfunction proposed byHalevi and Fuchs. This theory has the advantage to includedifferent models performed in the literature. According to this theory, the nonlocal dielectric function is described by a Lorenz-Drude like single oscillator model, in which the spatial dispersion effects are represented by an additional term depending on the square of the total wavevector k. The theory takes into account the scattering of the electromagneticexcitation at the surface of the dielectric material, which leads to the need of additional boundary conditions in order to solve Maxwell's equations and treat the electromagnetic transmission problem. The additional boundary conditions appear as additional surface scattering parameters in the expressions of the surface impedances. It is shown that the nonlocal modeling deviates from the classical $1/d^2$ law in the nanometerrangeat distances still larger than the ones where quantum effects are expected to come into play.