Collet Eric, Lemée-Cailleau Marie-Hélene, Buron-Le Cointe Marylise, Cailleau Hervé, Wulff Michael, Luty Tadeusz, Koshihara Shin-Ya, Meyer Mathias, Toupet Loic, Rabiller Philippe, Techert Simone
Groupe Matière Condensée et Matériaux, UMR CNRS 6626, Universite Rennes 1, 35042 Rennes Cedex, France.
Science. 2003 Apr 25;300(5619):612-5. doi: 10.1126/science.1082001.
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.
我们报告了使用单色100皮秒同步加速器脉冲通过X射线衍射对光致顺电-铁电结构相变的直接观测。这种相变发生在四硫富瓦烯-对氯醌中，这是一种电荷转移分子材料，其中电子和结构变化紧密耦合。一个300飞秒的光学激光脉冲在500皮秒的时间尺度上将材料从中性状态切换到离子状态，并凭借内在的协同作用产生自组织的长程结构有序。X射线数据表明激光照射后发生了宏观铁电重组。对激光照射前后结构的精修表明在分子水平上发生了结构变化。
