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Charge ordering and low-temperature lattice distortion in the β′ -(BEDT- TTF)2CF3CF2SO3 dimer Mott insulator
- Source :
- Physical Review B. 101
- Publication Year :
- 2020
- Publisher :
- American Physical Society (APS), 2020.
-
Abstract
- We present single-crystal x-ray diffraction measurements, optical investigations, and electronic structure calculations for the organic charge-transfer salt ${\ensuremath{\beta}}^{\ensuremath{'}}$-(BEDT-TTF)${}_{2}{\mathrm{CF}}_{3}{\mathrm{CF}}_{2}{\mathrm{SO}}_{3}$ 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 ${\ensuremath{\nu}}_{2}$ 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 ${\ensuremath{\nu}}_{3}$ mode in infrared spectra. At the same time, the sharp redshift of the ${\ensuremath{\nu}}_{1}$ 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 ${\mathrm{CF}}_{3}{\mathrm{CF}}_{2}{\mathrm{SO}}_{3}^{\ensuremath{-}}$ anion layer. These observations point to a subtle interplay of charge and lattice degrees of freedom at the phase transition.
- Subjects :
- Phase transition
Materials science
Mott insulator
Lattice (group)
Charge (physics)
02 engineering and technology
Crystal structure
Electronic structure
021001 nanoscience & nanotechnology
01 natural sciences
Optical conductivity
Charge ordering
Crystallography
Condensed Matter::Superconductivity
0103 physical sciences
Condensed Matter::Strongly Correlated Electrons
010306 general physics
0210 nano-technology
Subjects
Details
- ISSN :
- 24699969 and 24699950
- Volume :
- 101
- Database :
- OpenAIRE
- Journal :
- Physical Review B
- Accession number :
- edsair.doi...........be897e7a6cd0eb0bf21f36e5043e8ccc