title: Optical freezing of charge motion in an organic conductor.
abstract: Dynamical localization, that is, reduction of the intersite electronic transfer integral t by an alternating electric field, E(ω), is a promising strategy for controlling strongly correlated systems with a competing energy balance between t and the Coulomb repulsion energy. Here we describe a charge localization induced by the 9.3 MV cm(-1) instantaneous electric field of a 1.5 cycle (7 fs) infrared pulse in an organic conductor α-(bis[ethylenedithio]-tetrathiafulvalene)(2)I(3). A large reflectivity change of >25% and a coherent charge oscillation along the time axis reflect the opening of the charge ordering gap in the metallic phase. This optical freezing of charges, which is the reverse of the photoinduced melting of electronic orders, is attributed to the ~10% reduction of t driven by the strong, high-frequency (ω ≧ t/ħ) electric field.
authors.affiliation: Department of Physics, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Physics, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Yuto
authors.initials: Y
authors.lastname: Sagae
authors.affiliation: Department of Physics, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Yota
authors.initials: Y
authors.lastname: Naitoh
authors.affiliation: Department of Physics, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kawakami
authors.affiliation: 1] Department of Physics, Tohoku University, Sendai 980-8578, Japan [2] Japan Science and Technology Agency, CREST, Sendai 980-8578, Japan.
authors.forename: Hirotake
authors.initials: H
authors.lastname: Itoh
authors.affiliation: Department of Applied Physics, Okayama Science University, Okayama 700-0005, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: Toyota Physical and Chemical Research Institute, Nagakute 480-1192, Japan.
authors.forename: Kyuya
authors.initials: K
authors.lastname: Yakushi
authors.affiliation: Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Kishida
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Department of Physics, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Sumio
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: Department of Physics, Chuo University, Tokyo 112-8551, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Physics, Chuo University, Tokyo 112-8551, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yonemitsu
authors.affiliation: 1] Department of Physics, Tohoku University, Sendai 980-8578, Japan [2] Japan Science and Technology Agency, CREST, Sendai 980-8578, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Iwai