Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 27: CE: Poster Session
TT 27.32: Poster
Wednesday, March 24, 2010, 14:00–18:00, Poster D1
The metal-to-insulator transition in organic charge-transfer salts studied by noise spectroscopy — •Robert Rommel1, Pintu Das1, Adham Amyan1, Jens Müller1, Jens Brandenburg2, and Dieter Schweitzer3 — 1Goethe-Universität Frankfurt, SFB/TR49, Frankfurt am Main — 2Max-Planck-Institute for Chemical Physics of Solids, Dresden — 33. Physikalisches Institut, Universität Stuttgart
The organic (ET)2X compounds are model systems for low-dimensional metals exhibiting both strong electronic correlations and electron-phonon interactions. In particular, the interplay of onsite and intersite Coulomb interaction on the one hand and the coupling to the lattice degrees of freedom on the other hand are interesting to investigate with respect to the different kinds of metal-to-insulator transition (MIT) in this class of materials. We employ a new technique, fluctuation (noise) spectroscopy, for the quasi-2D (ET)2X salts to study the low frequency dynamics of the correlated electrons. Our experimental setup allows for measuring the resistance fluctuations in the frequency range from 1 mHz to above 100 Hz for systems showing an MIT in a wide temperature range covering variations of the samples’ resistance noise of many orders of magnitude (e.g. 10−8 − 106 Ω2/Hz). We employ a simple random fluctuation model to study the distribution of activation energies of the specific fluctuations causing the excess, 1/f-type noise. We compare different kinds of MIT regarding the mechanisms for slow electron dynamics.