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TT: Fachverband Tiefe Temperaturen
TT 28: Correlated Electrons: Low-dimensional Systems - Materials 2
TT 28.10: Talk
Wednesday, March 28, 2012, 17:30–17:45, H 0104
Single crystals and thin films of the new organic charge transfer compound (BEDT-TTF)-DTF — •Kai Ackermann1, Milan Rudloff1, Michael Bolte2, Harald Jeschke3, Matthias Wagner2, Roser Valenti3, and Michael Huth1 — 1Physikalisches Institut, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main — 2Institut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Straße 7, 60438 Frankfurt am Main — 3Institut für Theoretische Physik, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main
We investigate the structural and electronic properties of the semiconducting organic charge transfer system (BEDT-TTF)-DTF [bis(ethylenedithio)-tetrathiafulvalene - 9-dicyanomethy-lene-2,4,7-trinitrofluorene]. Crystal structure analysis and X-ray diffractometry show two different phases with monoclinic and triclinic symmetry. Both have a mixed stack configuration with a 1:1 ratio of BEDT-TTF to DTF. A characteristic of the triclinic phase is the layered structure of donor and acceptor molecules. Single crystals of both phases, which are grown from solution, were characterized by temperature-dependent (1.5K - 300K) conductivity measurements in three crystallographic directions and IR-spectroscopy for determining the charge transfer degree. First results of thin film deposition experiments by using organic molecular beam deposition are presented. These films allow to measure the frequency-dependent (20Hz - 100kHz) dielectric constant. The experimental results are discussed in view of band structure calculation within the framework of density functional theory.