Phonon-dominated energy transport in purely metallic heterostructures

We use ultrafast x-ray diffraction to quantify the transport of energy in laser-excited nanoscale Au/Ni bilayers. Electron transport and efficient electron-phonon coupling in Ni convert the laser-deposited energy in the conduction electrons within a few picoseconds into a strong non-equilibrium betw...

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Bibliographic Details
Main Authors Herzog, M, von Reppert, A, Pudell, J. -E, Henkel, C, Kronseder, M, Back, C. H, Maznev, A, Bargheer, M
Format Journal Article
LanguageEnglish
Published 26.03.2022
Subjects
Physics - Materials Science
Physics - Mesoscale and Nanoscale Physics
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Summary:We use ultrafast x-ray diffraction to quantify the transport of energy in laser-excited nanoscale Au/Ni bilayers. Electron transport and efficient electron-phonon coupling in Ni convert the laser-deposited energy in the conduction electrons within a few picoseconds into a strong non-equilibrium between hot Ni and cold Au phonons at the bilayer interface. Modeling of the subsequent equilibration dynamics within various two-temperature models confirms that for ultrathin Au films the thermal transport is dominated by phonons instead of conduction electrons because of the weak electron-phonon coupling in Au.
DOI:10.48550/arxiv.2203.14061