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Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Photoexcitations in a 1D manganite model: From quasiclassical light absorption to quasiparticle relaxations
 Online im WWW, 2016, arXiv:1610.07246, 27 pp. ITWMBerichte 

 English 
 Report, Electronic Publication 
 Fraunhofer ITWM () 
Abstract
We investigate the behavior of 1D correlated systems following a photoexcitation by combining abinitio methods, timedependent matrix product state (MPS) approaches, analytical insights from quantum Boltzmann equations, and molecular dynamics (MD) simulations to describe the dynamics on different time scales ranging from femtoseconds up to nanoseconds. This is done for manganite systems in the material class Pr1−xCaxMnO3. We derive onedimensional abinitio model Hamiltonians for which we compute the ground states at different values of the doping using MD simulations. At half doping, we obtain a magnetic microstructure of alternating dimers which we use as a starting point to formulate a onedimensional Hubbardtype model. In this strongly correlated 1D system we address the formation of quasiparticles after photoexcitations. We introduce a quasiclassical model for the absorption process of light which takes into account the backaction of the electrons to the electromagnetic field and compare the results with the ones obtained with a Peierls substitution ansatz in which we neglect the backaction. Taking this effect into account leads to a stronger response since the emitted radiation can be reabsorbed by neighboring particles. We use the resulting state as starting point for the shorttime dynamics which we obtain from 'numerically exact' MPS calculations. The dynamics is analyzed concerning the formation and lifetime of quasiparticles which form a starting point for the description of the relaxation process via a linearized quantum Boltzmann equation. In this way, our work constitutes a first step to building a unifying theoretical framework for the description of photoexcitations in strongly correlated materials over a wide range of time scales, capable of making predictions for ongoing experiments investigating pumpprobe situations and unconventional photovoltaics.