Ultrahigh-Efficiency Thermal Rectification via Topological Transition of Photonic Density of States and Near-Field Radiation Gap Variations

Near-field thermal rectifiers are essential for thermal management, thermal logic calculation, and energy conversion. However, current rectifier designs rely primarily on material response characteristics to different temperatures, which compromise spectral matching, reduce heat flux, and limit their rectification effectiveness. To address this significant challenge, we present a near-field thermal rectifier based on a multilayer structure that simultaneously achieves hyperbolic mode conversion and radiation gap modulation within a heat-transfer system. This approach allows us to achieve an ultrahigh thermal rectification factor of approximately 28,000 (at a typical temperature difference of 100 K). Moreover, this scheme demonstrates strong robustness to temperature changes and can produce significant thermal rectification effects, even under minimal temperature differences. The proposed rectification solution is simple and readily implemented, and further improvements can be achieved by designing graphene hybridization or other heterostructures. This study offers novel insights into utilizing structural advantages to design innovative near-field radiative thermal rectifiers and could be applied to advanced thermal management and energy conversion systems.