Researchers at the Department of Energy’s Oak Ridge National Laboratory made the first observations of waves of atomic rearrangements, known as phasons, propagating supersonically through a vibrating crystal lattice–a discovery that may dramatically improve heat transport in insulators and enable new strategies for heat management in future electronics devices.
“The discovery gives you a different way to control the flow of heat,” said lead author Michael Manley of the paper published in Nature Communications. “It provides a shortcut through the material–a way to send the energy of pure atomic motion at a speed that’s higher than you can with phonons [atomic vibrations]. This shortcut may open possibilities in heat management of nanoscale materials. Imagine the possibility of a thermal circuit breaker, for example.”
The scientists used neutron scattering to measure phasons with velocities about 2.8 times and about 4.3 times faster than the natural “speed limits” of longitudinal and transverse acoustic waves, respectively. “We didn’t expect them to be going that fast without [fading],” Manley said.
Insulators are necessary in electronic devices to prevent short circuits; but without free electrons, thermal transport is limited to the energy of atomic motion. Hence, understanding the transport of heat by atomic motion in insulators is important.