Researchers at the Department of Energy's Oak Ridge National Laboratory (ORNL), working with The Ohio State University and Amphenol Corporation, have uncovered a surprising new way to control how heat moves through solid materials. Their findings challenge long held assumptions about heat transport and could lead to more efficient cooling systems, energy devices, and electronic technologies.
Published in PRX Energy, the study found that applying an electric field to a specialized ceramic changes the behavior of phonons, the tiny atomic vibrations responsible for carrying heat. When the atoms vibrate in the same direction as the electric field (poling direction), those phonons persist much longer than vibrations moving across it. As a result, heat travels almost three times more efficiently along the direction of the electric field than it does in other directions.
"Being able to control both how fast and in what manner heat flows could lead to devices that manage thermal energy far more efficiently," said Puspa Upreti, an ORNL postdoctoral research associate.
Why Controlling Heat Matters
The ability to direct heat efficiently is essential for many advanced technologies. These include solid state electronic cooling systems with no moving parts, devices that convert heat into electricity, chip based electronics, and cogeneration systems that capture and reuse waste heat from industrial processes.
