title: Pressure dependence of the metal-insulator transition in κ-(BEDT-TTF)2Hg(SCN)2Cl: optical and transport studies.
abstract: The two-dimensional organic conductor κ-(BEDT-TTF)2-Hg(SCN)2Cl exhibits a pronounced metal-insulator transition at [Formula: see text] K. From the splitting of the molecular vibrations, the phase transition can be unambiguously assigned to charge-ordering with [Formula: see text]. We have investigated the pressure evolution of this behavior by temperature-dependent electrical transport measurements and optical investigations applying hydrostatic pressure up to 12 kbar. The data reveal a mean-field like down-shift of [Formula: see text] with a critical pressure of [Formula: see text] kbar and a metallic state above the suppression of the charge-ordered state; no traces of superconductivity could be identified down to T  =  1.5 K. As the charge order [Formula: see text] sets in abruptly with decreasing temperature, its size remains unaffected by pressure. However, the fraction of charge imbalanced molecules decreases until it is completely absent above 1.6 kbar.
authors.affiliation: Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Löhle
authors.forename: E
authors.initials: E
authors.lastname: Rose
authors.forename: S
authors.initials: S
authors.lastname: Singh
authors.forename: R
authors.initials: R
authors.lastname: Beyer
authors.forename: E
authors.initials: E
authors.lastname: Tafra
authors.forename: T
authors.initials: T
authors.lastname: Ivek
authors.forename: E I
authors.initials: EI
authors.lastname: Zhilyaeva
authors.forename: R N
authors.initials: RN
authors.lastname: Lyubovskaya
authors.forename: M
authors.initials: M
authors.lastname: Dressel