Researchers show that heat as wave propagates through graphene




The diffusion of heat by two-dimensional materials such as graphene, goes through wavelike diffusion. Show that researchers at the EPFL in Switzerland. That outcome can be used in future research into the use of graphene for electronics.

The research , published in Nature Communications, is important because with the miniaturization of components, it is increasingly difficult to lose heat quickly enough. One of the solutions is to use materials that have a very high thermal conductivity in order to dissipate the heat quickly, such as graphene. Because heat behaves differently in materials of only a few atoms thick, the question is how the heat spreads, will first be answered correctly.

The researchers demonstrated that heat spreads in the form of a wave. This phenomenon had been observed before, but only at temperatures from absolute zero, according to a notice on the site of EPFL .

graphene phonon heat waves

Two-dimensional materials react differently to heat than three-dimensional. They have the property to transfer heat with extremely little loss, even at room temperature. Normally it transfers heat by crystalline materials through vibrating atoms. This vibration mode is called a phonon . If heat propagates through a three-dimensional material, which remain phonons with each other collide. All of these processes ensure that the conductivity of the material over longer distance is less. Only under extreme conditions, as the temperature goes closer to absolute zero, it is possible to guide with virtually no loss of heat.

EPFL researchers show that materials react differently in two-dimensional form. Even at room temperature, show virtually no heat loss to be able to be guided. This is caused by a phenomenon called ” second sound “, wherein heat with a wave-like motion moving through a material rather than through the more mechanical diffusion. Through the second sound move the phonons simultaneously over large distances.


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