title: Super-Planckian Electron Cooling in a van der Waals Stack.
abstract: Radiative heat transfer (RHT) between macroscopic bodies at separations that are much smaller than the thermal wavelength is ruled by evanescent electromagnetic modes and can be orders of magnitude more efficient than its far-field counterpart, which is described by the Stefan-Boltzmann law. In this Letter, we present a microscopic theory of RHT in van der Waals stacks comprising graphene and a natural hyperbolic material, i.e., hexagonal boron nitride (hBN). We demonstrate that RHT between hot carriers in graphene and hyperbolic phonon polaritons in hBN is extremely efficient at room temperature, leading to picosecond time scales for the carrier cooling dynamics.
authors.affiliation: Radboud University, Institute for Molecules and Materials, NL-6525 AJ Nijmegen, The Netherlands.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Principi
authors.affiliation: ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
authors.forename: Mark B
authors.initials: MB
authors.lastname: Lundeberg
authors.affiliation: ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
authors.forename: Niels C H
authors.initials: NC
authors.lastname: Hesp
authors.affiliation: ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
authors.forename: Klaas-Jan
authors.initials: KJ
authors.lastname: Tielrooij
authors.affiliation: ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.|ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain.
authors.forename: Frank H L
authors.initials: FH
authors.lastname: Koppens
authors.affiliation: Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, I-16163 Genova, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Polini