Reverse Heat and Electricity

Effective control of heat transfer is essential for energy conservation and carbon reduction. The active control of heat transfer by regulating phonon transport is more challenging than the achievements in electrical conduction. So far, active and reversible control of phonon transport or thermal conductivity k (i.e., thermal switching) has been explored through many different approaches. In practical applications, high-performance thermal switching should fulfill three key conditions: high switching ratio, large number of switching cycles, and short switching time. Despite extensive research on thermal switching methods for various materials, it is difficult to find a material that satisfies all three basic conditions at room temperature. Ferroelectric materials are potential candidates for thermal switching because of their fast dipole switching and electrically tunable domain structure, which can be used to modulate thermal conductivity through the effect of phonon domain wall scattering. However, the switching ratio in ferroelectrics is low due to the mismatch between the domain size and the phonon mean free range.

　　The research group of Zuhuang Chen at Harbin Institute of Technology (Shenzhen) has confirmed the existence of dipole-ordered arrangement in antiferroelectric PbZrO₃ with high switching ratio potential by using the X-ray diffraction reciprocal space mapping method at the BL02U2 surface diffraction line station, which in turn reported a low-voltage-driven, high switching ratio, fast, and long-life thermal switch, which is realized by employing a reversible adjustment of the number of atoms in the primordial unit of new mechanism is realized in antiferroelectric  PbZrO₃. The fabricated thermal switches can realize the transition from antiferroelectric to ferroelectric by controlling a small voltage, which in turn significantly changes their thermal properties, yielding up to twice the effect in the direction of heat transfer and satisfying the integration of PbZrO₃-based thermal switches with other systems. The related results were published in Science with the title “Low voltage–driven high-performance thermal switching in antiferroelectric PbZrO₃ thin films” (Science 382, 6676, 1265 (2023)).