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 trans-fer. 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 (MoS2), 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/d(2) dependence of heat flux is shown, consistent with Coulomb's law. The heat transfer capacity is sensitive to the dielectric prop-erties 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.