Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 10: Superconductivity - Properties, Electronic Structure, Order Parameter
TT 10.4: Vortrag
Dienstag, 27. März 2007, 10:15–10:30, H18
Theory for ultrafast dynamics in cuprates: Role of electron-phonon coupling — •Julia Unterhinninghofen1, Dirk Manske1, and Andreas Knorr2 — 1Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart — 2Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin
We present a theory for ultrafast nonequilibrium dynamics in cuprate superconductors. In a typical time-resolved spectroscopy experiment, the sample is exited with an intense laser pulse, creating nonequilibrium quasiparticles which subsequently can relax via various scattering processes, restoring the superconducting state. We use the method of density matrix theory to study the optical excitation and relaxation dynamics in cuprates from a microscopical viewpoint. In particular, we consider scattering with optical phonons, looking at the interplay between relaxation of the excited quasiparticles and the creation of nonequilibrium phonon distributions; the superconducting state is restored on a 10 picosecond timescale, while the phonons have longer relaxation times. Time-resolved pump-probe spectra are calculated and compared both to quasi-equilibrium models and experimental results.