J. Phys. IV France 114 (2004) 379
Charge-ordering in -(BEDT-TTF) 2MM (SCN) 4 [ M = Cs, Rb, Tl, M = Zn, Co]K. Suzuki1, 1, K. Yamamoto1, M. Uruichi1 and K. Yakushi1
1 The Graduate University for Advanced Studies and Institute for Molecular Science, Nishigonaka, Myodaiji-cho, Okazaki, Aichi, 444-8585, Japan
Vibrational spectra, x-ray scattering and electrical resistivity of -(BEDT-TTF) 2MM (SCN) 4, [ M = Cs, Rb, Tl, M = Zn, Co] were measured in various temperature ranges. Vibrational spectra with the aid of x-ray scattering manifested charge disproportionation and charge ordering in their low-temperature phases. Except -(BEDT-TTF) 2CsM (SCN) 4, the orthorhombic form provided a horizontal stripe. On the other hand, monoclinic -(BEDT-TTF) 2TlZn(SCN) 4 provided a diagonal stripe. The electronic state of the high-temperature phase is discussed based on the line shape of the Raman spectrum. Key words. Charge-ordering, BEDT-TTF, Raman spectroscopy, infrared spectroscopy.
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