Sub-picosecond photo-induced melting of a charge-ordered state in a perovskite manganite

Ultrafast melting of a charge-ordered state has been observed in the photo- irradiated colossal magnetoresistive compound Pro(0.7)Ca(0.3)MnO(3). Pump-a nd-probe spectroscopy experiments reveal the formation of a conducting phas e with typical features of an insulator-metal transition (IMT) after less t han 1 ps. This phase is metastable and can be maintained for about 1 mu s u nless it is stabilized persistently into a pathlike metallic region by an e lectric field. Although laser-induced lattice heating may play a role in th e initial excitation, electronic correlations are the dominant effect which leads to the formation of the metallic state upon the breakdown of the cha rge-ordered state.