Ballistic and Diffusive Thermal Conductivity of Graphene

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 μm 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.