The researchers from the Department of Energy’s Oak Ridge National Laboratory carried out a study and made a finding that sustains the about 100-year-old Einstein’s theory on how heat moves through solids. This new study had the goal of examining heat conduction in thermal insulators, those materials that block the transfer of heat.
“We saw evidence for what Einstein first proposed in 1911, that heat energy hops randomly from atom to atom in thermal insulators. The hopping is in addition to the normal heat flow through the collective vibration of atoms,” explained Lucas Lindsay, a scientist at the Department of Energy’s Oak Ridge National Laboratory.
However, the “hopping” is more detectable in poor heat conductor, while, on the other hand, this phenomenon is only barely observable in materials that are good transmitters for heat.
Einstein’s theory regarding heat conduction through solids sustained by a new study which can clear the path towards new thermal insulators
The result of this new study helped scientists better comprehend the heat conduction process in thermal insulators and advanced the development of new materials that could reduce and recover the heat waste in thermoelectrics field of activity.
Lucas Lindsay and his co-workers used a single thallium-based crystal to conduct their study. As they were heating up the sample, the researchers used complex vibration-sensing instruments and supercomputers to reveal how the heat travels. The scientists found out that the atomic vibrations within the thallium-based crystal were to slow to conduct high amounts of heat.
“Our predictions were two times lower than we observed from our experiments. We were initially baffled. This led to the observation that another heat transfer mechanism must be at play. The thallium-based material we studied has one of the lowest thermal conductivities of any crystal. Much of the vibrating energy is confined to single atoms, and the energy then hops randomly through the crystal,” explained Lucas Lindsay.
Besides sustaining the Einstein’s theory regarding heat conduction, the finding is also significant for the industry as it can be applied to lower energy costs, heat waste, and even carbon emissions.