Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 10: Superconductivity - Properties, Electronic Structure, Order Parameter

TT 10.4: Talk

Tuesday, March 27, 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.