Extreme Near-Field Heat Transfer Between Gold Surfaces

Abstract

Extreme near-field heat transfer between metallic surfaces is a subject of debate as the state-of-the-art theory and experiments are in disagreement on the energy carriers driving heat transport. In an effort to elucidate the physics of extreme near-field heat transfer between metallic surfaces, this Letter presents a comprehensive model combining radiation, acoustic phonon and electron transport across sub-10-nm vacuum gaps. The results obtained for gold surfaces show that in the absence of bias voltage, acoustic phonon transport is dominant for vacuum gaps smaller than ~2 nm. The application of a bias voltage significantly affects the dominant energy carriers as it increases the phonon contribution mediated by the long-range Coulomb force and the electron contribution due to a lower potential barrier. For a bias voltage of 0.6 V, acoustic phonon transport becomes dominant at a vacuum gap of 5 nm, whereas electron tunneling dominates at sub-1-nm vacuum gaps. The comparison of the theory against experimental data from the literature suggests that well-controlled measurements between metallic surfaces are needed to quantify the contributions of acoustic phonon and electron as a function of the bias voltage.

27 pages, 4 figures, 2 supplementary figures

References in corpus (3)

• Effects of spatial dispersion in near-field radiative heat transfer between two parallel metallic surfaces
• Acoustic Phonon Tunneling and Heat Transport due to Evanescent Electric Fields
• Vacuum induced phonon transfer between two solid dielectric materials: Illustrating the case of Casimir force coupling

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• Atomistic modeling of extreme near-field heat transport across nanogaps between two polar dielectric materials
• Coupling between conduction and near-field radiative heat transfer in tip-plane geometry
• Extreme near-field heat transfer between silica surfaces
• Radiative heat exchange driven by acoustic vibration modes between two solids at the atomic scale
• Residual surface charge mediated near-field radiative energy transfer: A topological insulator analog
• Electronic heat tunneling between two metals beyond the WKB approximation
• Superconducting Coherence Peak in Near-Field Radiative Heat Transfer
• Electron tunneling induced thermoelectric effects