J. Phys. IV France 114 (2004) 393
Raman studies of the charge ordering and semiconductor-metal phase transition in polymorphic forms of (BEDT-TTF) 2Br1.3I1.1Cl0.6R. Wojciechowski1, 1, A. Kowalska1, J. Ulanski1, M. Mas-Torrent2, E. Laukhina2, C. Rovira2, V. Tkacheva3, K. Yamamoto4 and K. Yakushi4
1 Department of Molecular Physics, Technical University of Lodz, 90-924 Lodz, Poland
2 Institut de Ciencia de Materials de Barcelona, Campus UAB, 08193, Barcelona, Spain
3 Institute of Problems of Chemical Physics, RAS, 142432 Chernogolovka, MD, Russia
4 Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan
Semiconductor to metal and semiconductor to insulator phase transitions in the " '- and '-(ET) 2Br 1.3I 1.1Cl 0.6 single crystals were investigated by Raman spectroscopy. A charge ordered nature of the insulating state of the '-phase was confirmed. For the metallic "-phase ( " ' above 185 K) the Raman spectrum shows more bands than expected from the number of the C=C stretching a g modes. Key words. Organic conductors, Raman spectroscopy, charge order.
© EDP Sciences 2004