Ballistic and Diffusive Thermal Conductivity of Graphene

Abstract

In electronics, cooling a device would seem to be as straightforward as putting a good thermal conductor on top. Graphene is one of the best thermal conductors and thus a natural choice, but realize that its thermal conductivity is a function of sample size $L$, and also strongly depends on temperature. Through extensive phonon-mode calculations, the authors show that graphene's maximum thermal conductivity occurs around 100 K, and that $L$ of just 10 $\ensuremath{\mu}$m is sufficient for maximum effect. With these results, one can engineer a device with optimal $L$ for a required thermal conductivity at a given temperature.