Regensburg 2019 – scientific programme

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DS: Fachverband Dünne Schichten

DS 14: Poster

DS 14.15: Poster

Tuesday, April 2, 2019, 17:00–20:00, Poster E

Ultrafast energy transport in nanoscopic metal-insulator multilayers - Electrons vs. phonons — •Marc Herzog¹, Jan-Etienne Pudell¹, Alexander von Reppert¹, Alexei Maznev², Matthias Kronseder³, Christian Back^3,4, Gregory Malinowski⁵, and Matias bargheer⁶ — ¹Institut für Physik und Astronomie, Universität Potsdam — ²Dept. of Chemistry, MIT — ³Institut für Experimentelle und Angewandte Physik, Universität Regensburg — ⁴Fakultät für Physik, TU München — ⁵Institut Jean Lamour, Université Lorraine — ⁶Helmholtz-Zentrum Berlin

The transport of heat (or energy in general) in nanoscopic heterostructures is of great interest on a fundamental as well as a technological level, e.g. in the context of thermal management in devices or heat-assisted magnetic recording. In metal-insulator metaerostructures heat can be conducted by diffusion of electrons and/or lattice vibrations. Using time-resolved x-ray diffraction, we recently observed a surprisingly large thermal equilibration time between two ultrathin films of Au and Ni of more than 80 ps [1]. A detailed analysis revealed a significant contribution of lattice heat transport although electrons typically dictate the thermophysical properties in these metals. Here, we extend such experiments to metallic multilayers with an incorporated few-nm insulating MgO layer to suppress electron transport and calibrate the heat transport by phonon diffusion. At length scales smaller than the phonon mean free path ballistic transport is expected to efficiently contribute. We thus discuss the possibility of ballistic phonon transport in such systems. [1] Pudell et al. Nat. Commun. 9, 3335 (2018).