High enhancement of near-field radiative heat transfer between nanoparticles via the surface modes of the dielectric thin film

Abstract

We study the radiative heat transfer between two nanoparticles placed above the thin film under the framework of the dipole approximation and reflection Green's function. We show a high enhancement of heat transfer between particles, owing to the antisymmetric and symmetric surface modes excited at a wide band. The presence of the SiC thin film produces four orders of magnitude of amplification for the case of SiC particles which support the localized surface phonon polaritons (SPhPs). Enhancement is caused by the intense surface modes excited at the particle resonance and further proved through spectral analysis. The thin film can also provide an enhancement at a considerable distance, different from the huge inhibitory effect exhibited in the semi-infinite slab case. We address the role of the interparticle distance in the enhancement of heat flux by analyzing the SPhPs propagation length above the thin film. Finally, we show the thin film can intensify the coupling between SiC and doped Si particles, bringing out a high enhancement of radiative heat transfer between two particles with dissimilar materials. This enhancement is also attributed to the strong antisymmetric modes that amplify the emitted electric field energy density in the half-space from the SiC particle. This type of strong amplification can play an essential role in thermal tuning in the nanoparticle system.