Self-adaptive near-field radiative thermal modulation using a thermally sensitive bimaterial structure

The active control of the near-field radiative heat transfer has recently aroused significant attention. The common methods include utilizing phase-change materials, applying external electric or magnetic field and regulating the chemical potential. Herein, we propose a self-adaptive near-field radiative thermal modulation using a thermally sensitive bimaterial structure composed of gold and silicon nitride. Due to the huge differences between their Young's moduli and thermal expansion coefficients, the bimaterial structure has a bending tendency upon a sudden temperature change. The curved surface has a significant influence on the near-field radiative thermal transport, which largely depends on the separation gap between the two spaced objects. Two different bending scenarios are discussed, and the bimaterial structure can both spontaneously recover to its original planar state through self-adaptive thermal regulation. 24-fold and 4.4-fold variations in small-scale radiative heat transfer are demonstrated, respectively, for a 5 °C rise and 1 °C drop of the bimaterial. This work opens avenues for a dynamic and self-adaptive near-field radiative thermal modulation, and a large tuning range is worthy of expectation.