Scientists have developed a programmable material capable of directing heat on demand, a breakthrough that could reshape energy systems, infrared sensors and future memory devices, according to Osaka Metropolitan University.
The work tackles a physical rule called reciprocity, which normally links how efficiently a surface absorbs heat with how it emits heat. If a material takes in thermal energy well from a certain direction or wavelength, it typically releases heat the same way. This coupling has long limited engineers' ability to control the flow of thermal energy with precision.
Breaking that link could allow a material to absorb heat from one direction while releasing it in another, improving thermal management, energy conversion, infrared sensing and thermal communication technologies.
An international team led by Professor Koichi Okamoto and Dr. Shunsuke Murai, of Osaka Metropolitan University's Graduate School of Engineering, addressed the problem by combining a magneto-optical material with a phase change material known as GST. Magneto-optical materials shift how they interact with light when placed in a magnetic field, which in turn alters their thermal behavior.
Heat that remembers its settings
The resulting device can control the direction in which heat radiates, switch that behavior on or off, and hold its configuration even after power is switched off — much like data stored in a computer chip.
"We made heat radiation behave in a 'smarter' way," Dr. Murai said. "Achieving these capabilities in a working model could enable a new generation of efficient infrared emitters, thermal-energy devices, sensors, and photonic memory technologies."
The device also performed well with light striking it almost head-on, the researchers found. Earlier technologies generally needed light to hit a material at very steep angles to achieve comparable directional effects, which reduced how efficiently the material absorbed and radiated heat.
Previous systems had other drawbacks as well: inconsistent switching between "on" and "off" states, and a tendency to lose their configuration once power was cut. The new material switches states reliably while retaining its memory, according to the team, making it more practical for real-world use.
The researchers frame the work as a step toward devices that manage heat with the same precision electronic circuits use to control electricity.
"Our ultimate goal is to develop compact devices that can actively control heat radiation, much like electronic circuits control the flow of electricity," Okamoto said. He added that such devices could enable smarter infrared sensors, more efficient energy systems, and new forms of photonic memory that store information using light and heat rather than electrical charge.
The findings were published in the journal Laser.