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Ultrafast x-ray diffraction studies of photoexcited coherent phonons in SrRuO3 thin films

2013/01/15 by Daniel Schick, Peter Gaal, Schick, Daniel +15
Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #cond-mat.mes-hall #cond-mat.mtrl-sci

paper · pdf · doi:10.48550/arxiv.1301.3324

10 pages, 6 figures

arxiv created 2013/01/15 · arxiv updated 2013/01/16

Abstract

We present ultrafast x-ray diffraction experiments on thin films of metallic SrRuO3 (SRO) after their excitation with ultrashort intense laser pulses. Depending on the layer thickness, the data exhibit a transient splitting of the (002) SRO Bragg peak evidencing the generation and propagation of sharp acoustic strain waves. These distinct structural dynamics are due to the exceptionally fast electron-phonon relaxation that gives rise to a quasi-instantaneous thermal stress in SRO. The interpretation is corroborated by numerical simulations which show excellent agreement with the experimental findings. Despite the qualitatively different lattice dynamics for different SRO layer thicknesses, we identify a universal evolution of the transient average layer strain. The inferred discrepancy of the thermal stress profile from the excitation profile may hint toward a temperature-dependent effective Grüneisen parameter of SRO.

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