Maximal near-field radiative heat transfer between two plates

TL;DR

This study investigates how different material models affect near-field radiative heat transfer between two plates at nanometric distances, identifying optimal parameters and confirming the maximum transfer occurs with identical materials.

Contribution

It provides a detailed comparison of Drude and Lorentz models for maximizing near-field heat transfer, including optimal parameters and validation of the maximal transfer hypothesis.

Findings

Optimal model parameters for maximum heat flux identified.

Exact and approximate calculation methods compared in accuracy.

Maximal heat transfer occurs when both plates are of identical material.

Abstract

A parametric study of Drude and Lorentz models performances in maximizing near-field radiative heat transfer between two semi-infinite planes separated by nanometric distances at room temperature is presented in this paper. Optimal parameters of these models that provide optical properties maximizing the radiative heat flux are reported and compared to real materials usually considered in similar studies, silicon carbide and heavily doped silicon in this case. Results are obtained by exact and approximate (in the extreme near-field regime and the electrostatic limit hypothesis) calculations. The two methods are compared in terms of accuracy and CPU resources consumption. Their differences are explained according to a mesoscopic description of near-field radiative heat transfer. Finally, the frequently assumed hypothesis which states a maximal radiative heat transfer when the two semi-infinite planes are of identical materials is numerically confirmed. Its subsequent practical constraints are then discussed.