Charge Ordering and Low-Temperature Lattice Distortion in the {beta}'-(BDT-TTF){sub 2}CF{sub 3}CF{sub 2}SO{sub 3} Dime Mott Insulator.
We present single-crystal x-ray diffraction measurements, optical investigations, and electronic structure calculations for the organic charge-transfer salt beta'-(BEDT-TTF)(2)CF3CF2SO3 synthesized by electrocrystallization. Electronic structure calculations confirm the quasi-one-dimensional behavior of the compound and optical conductivity measurements reveal the dimer-Mott insulating nature of the system. The splitting of the charge-sensitive nu(2) mode in Raman spectra demonstrates the onset of an interlayer charge-ordered phase below 25 K, also suggested by the crystal structure considerations. This transition is accompanied by clear signatures of a lattice distortion in the BEDT-TTF donor layer, as shown by a splitting of the vibrational nu(3) mode in infrared spectra. At the same time, the sharp redshift of the nu(1) mode involving the BEDT-TTF ethylene groups strongly suggests a significant modification of the hydrogen-type bonding present between the BEDT-TTF donor layer and the CF3CF2SO3- anion layer. These observations point to a subtle interplay of charge and lattice degrees of freedom at the phase transition.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); German Research Foundation (DFG)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1765952
- Journal Information:
- Physical Review B, Vol. 101, Issue 3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Charge ordering and structural transition in the new organic conductor {delta}'-(BEDT-TTF){sub 2}CF{sub 3}CF{sub 2}SO{sub 3}.
IR and raman spectra of {Beta}"-(BEDT-TTF){sub 2}RCH{sub 2}SO{sub 3} (R = SF{sub 5}, CF{sub 3}) : dimerization related to hydrogen bonding.