Violation of Boltzmann Equipartition Theorem in Angular Phonon Phase Space Slows down Nanoscale Heat Transfer in Ultrathin Heterofilms
| Autor: | C. Brand, Simone Wall, Verena Tinnemann, Mohammad Tajik, Bengt-Olaf Frost, Michael Horn-von Hoegen, Thorben Groven, Alexander von Hoegen, A. Hanisch-Blicharski, Jonas Fortmann, Fabian Thiemann |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Total internal reflection
Materials science Condensed matter physics Phonon Mean free path Mechanical Engineering Bioengineering General Chemistry Physik (inkl. Astronomie) Condensed Matter Physics Condensed Matter::Materials Science Phase space Condensed Matter::Superconductivity Thermal Heat transfer Interfacial thermal resistance General Materials Science Equipartition theorem |
| Zdroj: | Nano Letters |
| Popis: | Heat transfer through heterointerfaces is intrinsically hampered by a thermal boundary resistance originating from the discontinuity of the elastic properties. Here, we show that with shrinking dimensions the heat flow from an ultrathin epitaxial film through atomically flat interfaces into a single crystalline substrate is significantly reduced due to violation of Boltzmann equipartition theorem in the angular phonon phase space. For films thinner than the phonons mean free path, we find phonons trapped in the film by total internal reflection, thus suppressing heat transfer. Repopulation of those phonon states, which can escape the film through the interface by transmission and refraction, becomes the bottleneck for cooling. The resulting nonequipartition in the angular phonon phase space slows down the cooling by more than a factor of 2 compared to films governed by phonons diffuse scattering. These allow tailoring of the thermal interface conductance via manipulation of the interface. |
| Databáze: | OpenAIRE |
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