First-principles calculations of phonon transport across a vacuum gap

Abstract

Phonon transport across a vacuum gap separating intrinsic silicon crystals is predicted via the atomistic Green's function method combined with first-principles calculations of all interatomic force constants. The overlap of electron wave functions in the vacuum gap generates weak covalent interaction between the silicon surfaces, thus creating a pathway for phonons. Phonon transport, dominated by acoustic modes, exceeds near-field radiation for vacuum gaps smaller than ~ 1 nm. The first-principles-based approach proposed in this work is critical to accurately quantify the contribution of phonon transport to heat transfer in the extreme near field.

31 pages, 4 figures, 4 supplemental figures

References in corpus (4)

• Contactless heat flux control with photonic devices
• 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
• Extreme Near-Field Heat Transfer Between Gold Surfaces

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• Extreme near-field heat transfer between silica surfaces
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• Complete tunneling of acoustic waves between closely spaced piezoelectric crystals
• Electronic heat tunneling between two metals beyond the WKB approximation
• Thermoelectric response enhanced by surface/edge states in physical nanogaps
• Crystal Orientation Dependence of Extreme Near-Field Heat Transfer between Polar Materials Governed by Surface Phonon Modes