title: Multistability in a BEDT-TTF based molecular conductor.
abstract: The low dimensional organic conductor (BEDT-TTF)(2)Br(1.3)I(1.1)Cl(0.6) [BEDT-TTF = bis(ethylenedithio)tertathiafulvalene] is shown to be a unique molecular solid that exists in three crystalline polymorphic forms (alpha'-, alpha' "-, beta' '-phase) and, surprisingly, is able to adopt the same metal-like beta' '-phase at both low (T < 185 K) and high (T > 395 K) temperatures. Several crystals of the alpha'- and alpha' "-phases have been studied using three different techniques: dc-conductivity measurements, ESR spectroscopy, and X-ray diffraction analysis. All these techniques show the existence of the reversible semiconductor <--> metal (alpha' " <--> beta' ') phase transition at both high and low temperatures as well as the alpha' <--> alpha' " phase transition at high temperatures. The phase transitions of these polymorphs are characterized by huge hysteresis and dramatic changes in the transport and magnetic properties. Based on ab initio calculations, it is suggested that dipole-dipole interactions can play a key role in the rich polymorphism of this molecular solid.
authors.affiliation: Institut de Ciència de Materials de Barcelona (CSIC), Campus Universitari de Bellaterra, Spain. cun@icmab.es
authors.forename: Elena
authors.initials: E
authors.lastname: Laukhina
authors.forename: José
authors.initials: J
authors.lastname: Vidal-Gancedo
authors.forename: Vladimir
authors.initials: V
authors.lastname: Laukhin
authors.forename: Jaume
authors.initials: J
authors.lastname: Veciana
authors.forename: Igor
authors.initials: I
authors.lastname: Chuev
authors.forename: Vladislava
authors.initials: V
authors.lastname: Tkacheva
authors.forename: Klaus
authors.initials: K
authors.lastname: Wurst
authors.forename: Concepció
authors.initials: C
authors.lastname: Rovira