Generalized first-principles method to study near-field heat transfer mediated by Coulomb interaction

We present a general microscopic first-principles method to study the Coulomb-interaction-mediated heat transfer in near field. Using nonequilibrium Green's function formalism, we derive Caroli formulas for transfers between materials with translational invariance. The central physical quantities are screened Coulomb potential and spectrum of polarizability. Within random phase approximation, calculate polarizability using linear response density functional theory obtain from retarded Dyson equation. show that mediated by interaction is consistent $p$-polarized evanescent waves which dominate adopt single-layer graphene as an example two parallel sheets separated vacuum gap $d$. Our results saturation flux at extreme field different reported $1/d$ dependence local functions. calculated up $5\times10^4$ times more than black-body limit, $1/d^2$ shown large separations. From energy current density, infer near-field enhancement stems electron transitions around Fermi energy. With uniform strain, increases most distances while negative correlation moderate valid inhomogeneous macroscopic used conventional fluctuational electrodynamics would fail subnanometer scale.