First-Principles Method to Study Near-Field Radiative Heat Transfer

We present a general and convenient first-principles method to study near-field radiative heat transfer. We show that the Landauer-like expression of heat flux can be expressed in terms of a frequency- and wave-vector-dependent macroscopic dielectric function that can be obtained from the linear response density functional theory. A random phase approximation is used to calculate the response function. We compute the heat transfer in three systems: graphene, molybdenum disulfide (Mo_{S 2}), and hexagonal boron nitride (h -BN). Our results show that the near-field heat flux exceeds the black body limit by up to 4 orders of magnitude. With an increase of the distances between two parallel sheets, a 1 /d² dependence of heat flux is shown, consistent with Coulomb's law. The heat transfer capacity is sensitive to the dielectric properties of materials. Influences from chemical potential and temperature are also discussed. Our method can be applied to a wide range of materials including systems with inhomogeneities, which provides solid references for applications of both physics and engineering.