We investigated the ultrafast dynamics of photoinduced melting of charge and orbital order in a perovskite-type manganite, Nd0.5 Ca0.5 MnO3, by means of pump-probe reflection spectroscopy. By irradiation with a 20-fs laser pulse, only the charge sectors become melted within ∼30 fs through strong electron correlations. During this process the oxygen displacements associated with the ordered phase persist. These displacements are subsequently released accompanied by several coherent oscillations. The coherent oscillation corresponding to the Jahn-Teller mode has relatively large amplitude demonstrating that the orbital order plays a significant role on the stabilization of the charge order.
|Physical Review B - Condensed Matter and Materials Physics
|Published - 2009 Jun 24