Probing the photoinduced phase transition in (C2H5)2(CH3)2Sb[Pd(dmit)2]2

The dynamics of the photoinduced effect in the low temperature phase of (C2H5)2(CH3)2Sb[Pd(dmit)2]2 (Et2Me2Sb[Pd(dmit)2]2) salt was studied by using pump-probe time resolved reflection spectroscopy with the time resolution of about 120 fs. The observed photoinduced reflectivity change was highly efficient and spectral shape of the photoinduced state was similar to that of dimer Mott insulator. In addition, oscillatory structure in photoinduced signal due to coherent phonon was observed reflecting the structural modulation coupling with valence change of the dimer state ([Pd(dmit)2]2). We discuss the primary dynamics of the photoinduced phenomena in this salt at low temperature phase.