Tunable near-field radiative thermal regulator enabled by cylindrical cavity effect and many-body interaction

Thermal regulators, as functional devices that can dynamically switch their operational states in response to changing thermal conditions, play a critical role in energy management. In this work, we present a cylindrical cavity effect-induced near-field radiative thermal regulator based on the temperature-dependent phase-transition properties of VO₂. We find that the radiative heat transfer (RHT) between two terminals (i.e., nanoparticles) inside the cylindrical cavity is higher than that in the presence of the cylinder and semi-infinite slab over the entire temperature range. We investigate the dependence of RHT on cavity radius in the presence of different substrates and reveal a power exponential decay behavior of thermal conductance at smaller radii. The maximum switching ratio of the cavity effect-induced regulator can reach 160, which is substantially higher than that of other compared systems. However, with increasing radius, the cavity modes caused by the cylindrical cavity in the metallic phase can significantly increase the RHT compared to the insulating phase, thereby decreasing the regulation performance. In addition, by introducing intermediate nanoparticles between two terminals, we find that the multi-particle system shows higher switching ratios due to the coupling of many-body interaction and cylindrical cavity effect, highlighting the role of the many-body pathway in regulating and controlling energy transfer. These findings advance contactless thermal management strategies for micro/nanoelectronics, offering insights into dynamic control via tunable materials or external stimuli in engineering applications.