title: Down to the quantum limit at the neutral-to-ionic phase transition of (BEDT-TTF)-(ClMe-TCNQ): symmetry analysis and phase diagram.
abstract: We report on the neutral-to-ionic (N-I) phase transition in the one-dimensional organic complex (BEDT-TTF)-(ClMeTCNQ). The X-ray studies at room temperature show that the neutral phase of (BEDT-TTF)-(ClMeTCNQ) is already characterized by a polar long-range ordering, at variance with other charge-transfer compounds comprising noncentrosymmetric molecules. From a detailed neutron diffraction study of this complex under high pressure, we present the phase diagram of the N-I transition down to the quantum limit. We discuss the symmetry breaking associated with the transition and the evolution of its first-order character under pressure.
authors.affiliation: Institut Max von Laue - Paul Langevin, BP 156, 38042 Grenoble Cedex 9, France. lemee@ill.fr
authors.forename: M H
authors.initials: MH
authors.lastname: Lemée-Cailleau
authors.forename: E
authors.initials: E
authors.lastname: Collet
authors.forename: M
authors.initials: M
authors.lastname: Buron-Le Cointe
authors.forename: N
authors.initials: N
authors.lastname: Grach
authors.forename: B
authors.initials: B
authors.lastname: Ouladdiaf
authors.forename: F
authors.initials: F
authors.lastname: Moussa
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Y
authors.initials: Y
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Roisnel
authors.forename: H
authors.initials: H
authors.lastname: Cailleau
mesh_terms: D007477:Ions; D008968:Molecular Conformation; D033363:Neutron Diffraction; D009570:Nitriles / Q000737:chemistry*; D044367:Phase Transition; D011312:Pressure; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: C472948:BEDT-TTF; D007477:Ions; D009570:Nitriles; D013438:Sulfhydryl Compounds; C013703:tetracyanoquinodimethane