Self-adaptive photonic control of near-field radiative heat transfer: dual-terminal flux stabilization and ultrahigh rectification enabled by thermal expansion synergy

Near-field radiative heat transfer systems typically exhibit performance drift under temperature excursions and seldom provide multifunctionality. We present a fully passive architecture that integrates positive and negative thermal expansion materials to achieve both thermal rectification and flux stabilization simultaneously. The device exploits the strong inverse dependence of near-field heat flux on gap distance as the primary control mechanism, with temperature-dependent surface phonon polaritons providing auxiliary enhancement. This configuration delivers three key advances: dual-terminal flux stabilization that keeps the net heat flux within 5% under ±50 K symmetric fluctuations at both terminals, an operational window exceeding 100 K in emitter-temperature variation, and rectification efficiency exceeding 99% without compromising stabilization. The design is entirely passive, requiring no external power or feedback, and is broadly compatible with diverse materials. By tailoring polariton dispersion and evanescent-mode coupling through gap modulation, the platform advances photonic control of near-field thermal emission, combining diode-like directionality with autonomous flux stabilization, and establishes a path toward mid-infrared thermal photonic circuits, metasurface-based emitters, and radiative heat engines where both spectral selectivity and flux stability are essential.