Near-field thermal radiative transfer in assembled spherical systems composed of core-shell nanoparticles

Abstract

Thermal radiative transfer can be enhanced significantly when the distance of radiation sources is smaller than the characteristic wavelength of thermal radiation. However, the problem of the near-field thermal radiative transfer (NFTRT) between core-shell nanoparticles has rarely been studied. Moreover, most previous studies investigate the NFTRT between two or three nanoparticles, while few works have been done on real many-body systems where multibody mutual interaction plays a pivotal role. In this study, we choose silicon carbide (SiC) and n-type germanium (Ge) as two constituent materials of the core-shell nanoparticle, and describe a complete theoretical investigation of the NFTRT in many body systems composed of core-shell nanoparticles. The results demonstrate that the core-shell nanoparticles inherit both characteristics of SiC and n-type Ge: quasimonochromaticity and broad-band. What’s more, the spectral features can be tuned by core-shell radius and material composition. Further studies show that multibody mutual interaction has a detrimental effect on the NFTRT between two assembled spherical systems. Still, the enhancement of NFTRTs between a small proportion of nanoparticle dimers inside the systems is observed, which can be attributed to the coherence enhancement of fluctuating thermal fields. And by analyzing the trace of a dyadic Greens functions product, the locations of inherent resonance of nanoparticles and the coherent enhancement due to multibody mutual interaction need to be consistent if we hope strong exaltation effects of NFTRT.