Asymmetry-induced radiative heat transfer in Floquet systems

Time modulation opens new avenues for light, heat control, and energy harvesting, yet the impact of nonequilibrium dynamics of microscopic particles remains largely unexplored. We develop a microscopic theory to describe radiative heat transfer in such Floquet systems. Significant heat transfer occurs due to differences in electronic properties between parallel metal plates, despite identical driving protocols and temperatures. This arises from a unique exponential-staircase distribution of radiative photons, induced by nonequilibrium electronic fluctuations, and can be tuned via both microscopic properties and driving parameters. Our work highlights the importance of nonequilibrium microscopic details, unlocking new opportunities for active cooling, thermophotovoltaics, thermal imaging and manipulation, and carrier dynamics probing.