title: Lattice distortion stabilizes the photoinduced metallic phase in the charge-ordered organic salts (BEDT-TTF)3X2 (X=ReO4, ClO4).
abstract: Photoinduced effects caused by intramolecular excitation were investigated by simultaneous optical and transport measurement in two charge-ordered organic salts, (BEDT-TTF)3X2 (X=ReO4, ClO4) [BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene]. Although the two salts have the same molecular (average) charge and arrangement, they showed different photoinduced effects. A photoinduced insulator-to-metal phase transition with a metastable charge order-melting state was observed in the ReO4 salt where the charge ordered state is associated with the lattice distortion. On the other hand, no photoinduced insulator-to-metal phase transition was noted in the ClO4 salt where the charge ordered state is not accompanied by the lattice distortion. This comparative study suggested that the lattice distortion plays a key role in the stabilization of the photoinduced phase.
authors.affiliation: RIKEN, Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Takubo
authors.forename: Naoya
authors.initials: N
authors.lastname: Tajima
authors.forename: Hiroshi M
authors.initials: HM
authors.lastname: Yamamoto
authors.forename: HengBo
authors.initials: H
authors.lastname: Cui
authors.forename: Reizo
authors.initials: R
authors.lastname: Kato