Regensburg 2019 – scientific programme
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MA: Fachverband Magnetismus
MA 55: Electron theory and micromagnetism
MA 55.3: Talk
Friday, April 5, 2019, 10:00–10:15, H38
Coupled charge and spin dynamics in a photo-excited doped Mott insulator — •Nikolaj Bittner1, Denis Golez1, Hugo Strand2, Martin Eckstein3, and Philipp Werner1 — 1Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland — 2Flatiron Institute, Simons Foundation, 162 Fifth Avenue. New York, NY, 10010, USA — 3Department of Physics, University of Erlangen-Nuernberg, 91058 Erlangen, Germany
Using a nonequilibrium implementation of the extended dynamical mean field theory (EDMFT) we simulate the relaxation of a photo-excited doped Mott insulator. We consider the t-J model and focus on the interplay between the charge- and spin-dynamics in different excitation and doping regimes. The appearance of string states after a weak photo excitation manifests itself in a nontrivial scaling of the relaxation time with the exchange coupling. Moreover, we observe a correlated oscillatory evolution of the kinetic energy and spin-spin correlation function, which is a direct consequence of a strong spin-charge coupling. A strong excitation of the system, on the other hand, suppresses the spin correlations and results in a relaxation that is controlled by hole scattering. Finally, we propose a pump-probe setup, which allows to directly observe oscillations in the optical conductivity originating from string states.