Residual surface charge mediated near-field radiative energy transfer: A topological insulator analog

TL;DR

This paper investigates how residual surface charges influence near-field radiative energy transfer, revealing a topological insulator analog that enables modulation of NFRET in micro- and nano-systems, with temperature-dependent effects.

Contribution

It introduces a topological insulator analog model to modulate NFRET using common trivial materials, highlighting the role of residual surface charges and temperature effects.

Findings

Residual surface charges induce a new temperature-dependent heat flux mode.

At low temperatures, surface charges significantly enhance NFRET.

At higher temperatures, surface charges weaken NFRET due to dominant Fröhlich resonance.

Abstract

We study the modifications of near-field radiative energy transfer (NFRET) caused by residual surface charges, which are common in micro- and nano-systems like NEMS/MEMS. The host object with the residual surface charges and the inherent bulk state can be treated as an analog of the real three-dimensional topological insulator, which is inherent of also both surface states and bulk states and is promising to modulate NFRET. Through constructing such a topological insulator analog, we aim to modulate NFRET concerning only common trivial materials. Besides the well-known resonant modes (surface polariton and localized surface polariton) supported by the bulk state, the residual surface charges give rise to an additional temperature-dependent mode providing a new heat flux channel. For low temperatures we find a giant surface-charge-induced enhancement of the NFRET due to a good match between the surface-charge-induced resonance and the Planck window. However, for relative high temperatures where the Fr\"{o}hlich resonance dominates the heat transfer rather the surface-charge-induced resonance, the residual charges result in a weakening of the NFRET. This work paves way for understanding and modulating the near-field radiative energy transfer for micro- and nano-systems.