Photoexcitations in a 1D manganite model: From quasiclassical light absorption to quasiparticle relaxations

摘要

We investigate the evolution of a photoexcitation in a correlated materialover a wide range of time scales from femto- to nanoseconds. The system studiedis a one-dimensional model of a manganite with correlated electron, spin,orbital, and lattice degrees of freedom. In a first step, the interaction oflight with electrons considering the back-action is treated. Time-dependentmatrix product states (MPS) methods are then used for the electronic quantumdynamics of the resulting photoexcitation. The emergence of quasiparticles froma fully correlated excitation is addressed. We study the relaxation of thenon-equilibrium quasi-particle distribution with a linearized quantum-Boltzmannequation. Our investigation treats a model-Hamiltonian with parametersextracted from ab-initio calculations of Pr$_{1-x}$Ca$_{x}$MnO$_3$. This modelis restricted to one dimension. The ground state phases for the entirecomposition range are determined and rationalized by a coarse grained polaronmodel. A pattern of antiferromagnetically coupled Zener polarons for thehalf-doped material is identified, which forms the basis for the dynamicalcalculations discussed above. We discuss the effect of the resulting magneticmicrostructure on the relaxation times of the excitation.