Vortex matter as a magnetically programmable metasurface for tuning near-field radiative heat transfer

Abstract

Near-field radiative heat transfer (NFRHT) is of great interest for energy conversion and thermal management. Recent work on NFRHT has shown that metasurfaces can enhance NFRHT and reshape its spectral characteristics. Here, we show that the vortex lattice of a type-II superconductor represents a self-assembled metasurface whose lattice dimensions, in contrast to most other metasurfaces, can be tuned by magnetic fields, allowing NFRHT to be varied by orders of magnitude. Specifically, we show that for two Nb surfaces at 4.2 K and separated by a 100 nm gap, NFRHT can be magnetically tuned by a factor >200. Further, we show that the tuning range grows upon cooling, exceeding 10^5 at 2 K, which is far beyond the order-unity modulation of many proposed schemes for tuning NFRHT. Our results establish vortex matter as a magnetically programmable thermal metasurface and open new opportunities for tuning the flow of heat at the nanoscale.