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Condensed Matter, Materials Science, cond-mat.mtrl-sci
Abstract:
Platinum is an important component of heterostructures for novel photocatalysis and spintronic applications. Since these applications involve nonequilibrium states, knowledge of how platinum behaves in nonequilibrium conditions is desired. In particular, a quantitative determination of the electron-phonon coupling parameter Gep of bulk platinum is of importance. Here, we study the lattice response of platinum to laser excitation directly using femtosecond electron diffraction. We provide details about our new approach for analyzing time-resolved polycrystalline diffraction data, which extracts the lattice dynamics reliably by finding the best fit to the full transient diffraction pattern rather than by analyzing transient changes of individual Debye-Scherrer rings. Based on the results for the transient evolution of atomic mean squared displacement (MSD) in platinum and using a two-temperature model (TTM), we extract Gep = (3.14 ± 0.09) · 1017W⁄m3K. We find that within our range of absorbed energy densities, Gep is not
fluence-dependent. Our results for the lattice dynamics of platinum provide insights into electron-phonon coupling and phonon thermalization and constitute a basis for quantitative descriptions of platinum-based heterostructures in nonequilibrium conditions.
