Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 29: Correlated Electrons: Low-dimensional Systems - Materials 2

TT 29.8: Vortrag

Mittwoch, 25. März 2009, 16:00–16:15, HSZ 301

Thin films of charge transfer compounds of tetrathiafulvalene and its derivatives — •Vita Levitan and Michael Huth — Physikalisches Institut, Goethe-Universität, Frankfurt am Main, Germany

Thin films of the organic C(harge) T(ransfer) complex ET-TCNQ have been prepared by molecular beam epitaxy (MBE). We studied the growth of this compound by co-deposition and sequential deposition of two layers of ET and TCNQ molecules followed by a post growth annealing. At the layers’ interface ET-TCNQ has been detected and characterized by x-ray diffraction and energy dispersive x-ray spectroscopy as the monoclinic phase of ET-TCNQ. The electrical properties of the bilayer (such as conductivity) were measured and analyzed.

We also prepared thin films of TTF-TCNQ with a preferred orientation of the microcrystals on the substrate along the b-axis of TTF-TCNQ, being the highest conductivity axis of the compound. Various oxide-based substrate materials with orientations optimized for small layer-substrate lattice mismatch were chosen. We studied the influence of epitaxial clamping on the Peierls transition of TTF-TCNQ at about 60 K by means of temperature dependence transport measurement.

(TTF: tetrathiafulvalene, ET: bis(ethylenedithio)tetrathiafulvalene, TCNQ: tetracyanoquinodimethane)