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Relaxation of photoexcitations in polaron-induced magnetic microstructures

: Köhler, T.; Rajpurohit, S.; Schumann, O.; Paeckel, S.; Biebl, F.R.A.; Sotoudeh, M.; Kramer, S.C.; Blöchl, P.E.; Kehrein, S.; Manmana, S.R.


Physical Review. B 97 (2018), Nr.23, Art.235120
ISSN: 0163-1829
ISSN: 1098-0121
ISSN: 0556-2805
ISSN: 2469-9950
Fraunhofer ITWM ()

We investigate the evolution of a photoexcitation in correlated materials over a wide range of time scales. The system studied is a one-dimensional model of a manganite with correlated electron, spin, orbital, and lattice degrees of freedom, which we relate to the three-dimensional material Pr1−x CaxMnO3. The ground-state phases for the entire composition range are determined and rationalized by a coarse-grained polaron model. At half doping a pattern of antiferromagnetically coupled Zener polarons is realized. Using time-dependent density-matrix renormalization group (tDMRG), we treat the electronic quantum dynamics following the excitation. The emergence of quasiparticles is addressed, and the relaxation of the nonequilibrium quasiparticle distribution is investigated via a linearized quantum-Boltzmann equation. Our approach shows that the magnetic microstructure caused by the Zener polarons leads to an increase of the relaxation times of the excitation.