Unusual Two-stage Dynamics of the Spin-Lattice Polaron Formation
  We follow the formation of a spin-lattice polaron after a quantum quench that simulates absorption of the pump{pulse in the time-resolved experiments. We discover a two-stage relaxation where spin and lattice degrees of freedom represent an integral part of the relaxation mechanism. In the first stage the kinetic energy of the spin-lattice polaron relaxes towards its ground state value while relaxation processes via spin and phonon degrees of freedom remain roughly independent. In the second, typically much longer stage, a subsequent energy transfer between lattice and spin degrees of freedom via the charge carrier emerges. The excess local spin energy radiates away via magnon excitations. 
Jan Kogoj, Zala Lenarcic, Denis Golez, Marcin Mierzejewski, Peter   Prelovsek and Janez Bonca
cond-mat.str-el