Researchers at Osaka Metropolitan University have developed a material that can control, direct, and remember the flow of heat, without continuous power. The breakthrough breaks a fundamental physical principle called thermal reciprocity, which has long made it impossible to independently control how heat enters and leaves a material.
In most materials, absorption and emission are inseparable. If a surface absorbs heat efficiently from a particular direction, it emits heat the same way. The new device, developed by Professor Koichi Okamoto and Dr Shunsuke Murai, overcomes this limitation by pairing a magneto-optical material with a phase-change material known as GST (germanium-antimony-tellurium). When exposed to a magnetic field, the magneto-optical layer changes how it interacts with light, while the GST layer switches between amorphous and crystalline states to lock in the configuration.
The result is a device that can direct thermal radiation to a specific location, switch that behavior on or off, and retain its settings after power is removed, analogous to how data is stored and controlled inside a computer chip. The work was published in the journal Laser & Photonics Reviews under the title “Reconfigurable Giant Nonreciprocity at Near-Normal Incidence via Phase-Change Magneto-Optical Metagratings.”
Potential applications span infrared sensors that can switch between detection modes, energy systems that waste less heat, and a new class of photonic memory devices that use light and heat instead of electrical charges. The ability to program heat flow without continuous power consumption could eventually aid chip cooling in dense AI hardware and improve thermal management in silicon photonics, where heat dissipation is a growing bottleneck as transistor densities increase.
The research team noted that while the current device is a proof of concept, the underlying principle is general and could be adapted to different wavelengths and operating conditions for practical deployment.
Sources: Researchers create programmable material that can steer heat and remember its state without power (Tom’s Hardware, July 2026); Incredible new material makes heat programmable (ScienceDaily/Osaka Metropolitan University, July 7, 2026)