|By Le Williams | 2 years ago|
A substantial breakthrough by researchers at the Department of Energy’s Oak Ridge National Laboratory supports a theory by Albert Einstein that explains how heat moves through all objects.
“We saw evidence for what Einstein first proposed in 1911—that heat energy hops randomly from atom to atom in thermal insulators,” said Lucas Lindsay, materials theorist at ORNL. “The hopping is in addition to the normal heat flow through the collective vibration of atoms.”
This observation advances understanding of heat conduction in thermal insulators and will aid the discovery of novel materials for applications from thermoelectrics that recover waste heat to barrier coatings that prevent transmission of heat.
Lindsay and his colleagues used sophisticated vibration-sensing tools to detect the motion of atoms and supercomputers to simulate the journey of heat through a simple thallium-based crystal. Their analysis revealed that the atomic vibrations in the crystal lattice were too sluggish to transmit much heat.
“Our predictions were two times lower than we observed from our experiments. We were initially baffled,” Lindsay said. “This led to the observation that another heat transfer mechanism must be at play.”
Meantime, heat-hopping may only be detectable in optimal thermal insulators. “However, this heat-hopping channel may well be present in other crystalline solids, creating a new lever for managing heat,” he said.