Photo-Induced Dynamics of Charge/Orbital Order in Perovskite Manganite Nd_(0.5)Ca_(0.5)MnO_3

摘要

Dynamics of charge/orbital order has been investigated for Nd_(0.5)Ca_(0.5)MnO_3 with femtosecond pumpprobe spectroscopy. Photo-induced changes in polarized reflectance spectra and their temporal behavior were measured for the detwinned single crystal. Marked shrinkage of charge gap as well as decrease in optical anisotropy due to partial melting of charge/orbital order is observed upon photo-excitation. Melting of charge/orbital order occurs at first within the excitation pulse duration, and then followed by relaxation of the lattice system via thermal contact with electron system with the relaxation time of approximately 1 ps.