Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 48: Poster Surface Dynamics

O 48.3: Poster

Dienstag, 18. März 2025, 18:00–20:00, P2

Ultrafast LEED Study of Bismuth Thin Films on Silicon (001) — •Nandana V Uday¹, Felix Kurtz¹, Jonas Fortmann³, Alp Akbiyik¹, Michael Horn-von-Hoegen^3,4, and Claus Ropers^1,2 — ¹)Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany — ²4th Physical Institute ,Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany — ³University of Duisburg-Essen, 47057 Duisburg, Germany — ⁴Center for Nanointegration (CENIDE), 47057 Duisburg, Germany

The interface between two materials in a heterostructure serves as a barrier to the diffusion of thermal energy, thereby hindering heat flow across the boundary. On the nanoscale, heat transport may further be modified. Recently, it was shown that the thermal transport from Bi film into a Si substrate is reduced for films thinner than the phonon mean free path, due to phonon trapping by total internal reflection [1]. To study the non-equilibrium phonon dynamics in this process, ultrafast low-energy electron diffraction (ULEED) is suitable and direct means providing ultrafast temporal and high momentum resolutions. By analyzing the momentum-resolved map of a transient inelastic scattering background [2], we aim to identify phonon trapping, depopulation, and thermalization. As a first step, we monitor the heat transfer by phonons through the thin film-substrate interface, extracting cooling times from the transient lattice temperature of the bismuth film.

Keywords: ULEED; Ultrathin Bi film; Nanoscale Heat Transport; Phonon trapping; Momentum-resolved maps