title: Laser-induced ferroelectric structural order in an organic charge-transfer crystal.
abstract: We report the direct observation by x-ray diffraction of a photoinduced paraelectric-to-ferroelectric structural phase transition using monochromatic 100-picosecond synchrotron pulses. It occurs in tetrathiafulvalene-p-chloranil, a charge-transfer molecular material in which electronic and structural changes are strongly coupled. An optical 300-femtosecond laser pulse switches the material from a neutral to an ionic state on a 500-picosecond time scale and, by virtue of intrinsic cooperativity, generates self-organized long-range structural order. The x-ray data indicate a macroscopic ferroelectric reorganization after the laser irradiation. Refinement of the structures before and after laser irradiation indicates structural changes at the molecular level.
authors.affiliation: Groupe Matière Condensée et Matériaux, UMR CNRS 6626, Universite Rennes 1, 35042 Rennes Cedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Collet
authors.forename: Marie-Hélene
authors.initials: MH
authors.lastname: Lemée-Cailleau
authors.forename: Marylise
authors.initials: M
authors.lastname: Buron-Le Cointe
authors.forename: Hervé
authors.initials: H
authors.lastname: Cailleau
authors.forename: Michael
authors.initials: M
authors.lastname: Wulff
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Luty
authors.forename: Shin-Ya
authors.initials: SY
authors.lastname: Koshihara
authors.forename: Mathias
authors.initials: M
authors.lastname: Meyer
authors.forename: Loic
authors.initials: L
authors.lastname: Toupet
authors.forename: Philippe
authors.initials: P
authors.lastname: Rabiller
authors.forename: Simone
authors.initials: S
authors.lastname: Techert