Japanese Scientists Create Material That Controls Heat and Retains Memory Without Power
Japanese Scientists Create Material That Controls Heat and Retains Memory Without Power
A group of researchers from Osaka Metropolitan University has developed a programmable thermal device capable of controlling how heat is emitted and maintaining its configuration even after the power is removed. The study, published in the journal Laser & Photonics Reviews, could represent a breakthrough for thermal management in future high-performance chips, silicon photonic systems, infrared sensors, and energy recovery technologies.
The new solution addresses two major issues that have so far limited the development of non-reciprocal thermal devices. The system combines a magneto-optical material that can modify light behavior in the presence of a magnetic field with germanium-antimony-telluride (GST), a phase-change material that can maintain its programmed state even without power.
In traditional materials, the behavior of heat absorption and emission follows Kirchhoff's law of thermal radiation. In practice, a surface that effectively absorbs energy at a specific wavelength and direction must also emit it in the same manner. This relationship limits the ability to independently control heat transfer.
The Material Capable of Controlling Heat: The New Frontier of Thermal Technology
Overcoming this constraint could offer new opportunities for thermal energy management. Technologies capable of separating absorption and emission could improve radiative cooling systems, thermophotovoltaic devices, thermal communications, and applications based on infrared radiation. The Japanese team used a magneto-optical semiconductor made of indium arsenide (InAs), which allows for directional behavior of infrared radiation due to its interaction with a magnetic field.
Above this material, a microscopic grid structure made of GST was created. The latter functions as a non-volatile memory, switching between amorphous and crystalline states and reversibly altering the optical properties of the device. Thanks to this combination, the system can be programmed to change the way it emits heat and retain that setting without requiring constant power.
The magnetic field enables the regulation of radiation behavior, while the phase change of GST allows for saving the chosen configuration. According to the researchers, the prototype has achieved a high level of non-reciprocity, with a value close to 0.9, operating at an incidence angle of only three degrees, much closer to the frontal position compared to previous systems that required extremely tilted angles.
The technology is still experimental and not yet ready for commercial applications.