Laser-induced ferroelectric structural order in an organic charge-transfer crystal.
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.
Collet
Eric
E
Groupe Matière Condensée et Matériaux, UMR CNRS 6626, Universite Rennes 1, 35042 Rennes Cedex, France.
Lemée-Cailleau
Marie-Hélene
MH
Buron-Le Cointe
Marylise
M
Cailleau
Hervé
H
Wulff
Michael
M
Luty
Tadeusz
T
Koshihara
Shin-Ya
SY
Meyer
Mathias
M
Toupet
Loic
L
Rabiller
Philippe
P
Techert
Simone
S