title: Probing the metal-insulator phase transition in the (DMEDO-EBDT)2PF6 single crystal by optical measurements.
abstract: The temperature and polarization dependence of the optical reflectivity  spectra of a quasi-one-dimensional 1/4-filled band system, (DMEDO-EBDT)(2)PF(6), have been investigated. We observed clear anisotropy in the electronic structures corresponding to the anisotropic transport properties. The appearance of a charge gap (E(g) > 0.1 eV) and transfer of the spectral weight accompanied by the metal-insulator phase transition were clearly observed. In addition, a split of the intramolecular vibrational modes was observed, which strongly suggested the existence of charge disproportionation in the low temperature phase. We also observed a photoinduced reflectivity change, which implied the occurrence of a photoinduced phase transition from the low temperature insulating phase to the high temperature metallic phase.
authors.affiliation: Department of Materials Science, Tokyo Institute of Technology, 2-12-1, Oh-okayama, Meguro-ku, Tokyo, Japan. tishi@chem.titech.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: M
authors.initials: M
authors.lastname: Kitayama
authors.forename: A
authors.initials: A
authors.lastname: Chono
authors.forename: K
authors.initials: K
authors.lastname: Onda
authors.forename: Y
authors.initials: Y
authors.lastname: Okimoto
authors.forename: S
authors.initials: S
authors.lastname: Koshihara
authors.forename: Y
authors.initials: Y
authors.lastname: Nakano
authors.forename: H
authors.initials: H
authors.lastname: Yamochi
authors.forename: T
authors.initials: T
authors.lastname: Morikawa
authors.forename: T
authors.initials: T
authors.lastname: Shirahata
authors.forename: Y
authors.initials: Y
authors.lastname: Misaki