New findings from researchers at the Oak Ridge National Laboratory of the US Department of Energy (ORNL) support a theory proposed by Albert Einstein in 1911 that explains how heat moves through solids.
In a study in the journal Science scientists studied a class of materials known as heat insulators that block heat transfer – a fundamental natural process.
"We saw evidence for what Einstein suggested in 1911 – that heat energy randomly hops from atom to atom in thermal insulators," said Lucas Lindsay, a materials scientist at ORNL, in a statement. "The hopping is in addition to the normal heat flow through the collective vibration of the atoms."
In materials that conduct heat easily, this random energy hopping is not very noticeable, the researchers said. However, it shows in those who can transfer less heat.
The results will help scientists better understand how heat travels in thermal insulators. This could lead to the development of new materials that recover waste heat or prevent heat transfer. These materials could drastically reduce energy costs and CO 2 emissions, according to the ORNL team.
To make this discovery, the researchers used sophisticated vibration-sensitive devices and supercomputers to simulate and simulate the movement of atoms made of the chemical element thallium ̵
They found that the vibration of atoms in the crystal – arranged in a lattice – does not contain enough energy to transmit much heat. However, they still observed signs of heat transfer that were not included in their predictions.
"Our predictions were twice lower than we observed in our experiments, and we were stunned at first," Lindsay said. "This led to the observation that another heat transfer mechanism must be in play."
This "other mechanism" is the heat-jumping described by Einstein.
At present, this process may only be detectable in highly insulating materials, Lindsay said, but it could also be present in other crystalline solids, creating new opportunities for the management of heat.