Schick, D.; Herzog, M.; Bojahr, A.; Leitenberger, W.; Hertwig, A.; Shayduk, R.; Bargheer, M.: Ultrafast lattice response of photoexcited thin films studied by X-ray diffraction. Structural Dynamics 1 (2014), p. 064501/1-13
10.1063/1.4901228
Open Access Version
Abstract:
Using ultrafast X-ray diffraction, we study the coherent picosecond lattice dynamics of photoexcited thin films in the two limiting cases, where the photoinduced stress profile decays on a length scale larger and smaller than the film thickness. We solve a unifying analytical model of the strain propagation for acoustic impedance-matched opaque films on a semi-infinite transparent substrate, showing that the lattice dynamics essentially depend on two parameters: One for the spatial profile and one for the amplitude of the strain. We illustrate the results by comparison with high-quality ultrafast X-ray diffraction data of SrRuO3 films on SrTiO3 substrates.