Regensburg 2013 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 40: Poster Session Correlated Electrons

TT 40.48: Poster

Wednesday, March 13, 2013, 15:00–19:00, Poster D

New insight in the glass-like dynamics of the organic charge-transfer salts κ-(BEDT-TTF)₂X from fluctuation spectroscopy — •Benedikt Hartmann¹, Robert Rommel¹, Jens Brandenburg¹, John Schlueter², and Jens Müller¹ — ¹Institute of Physics, Goethe-University Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt (M) — ²Argonne National Laboratory, Materials Science Division, Argonne, IL, USA

The organic molecular conductors κ-(BEDT-TTF)₂X are model systems for studying the physics of correlated electrons in reduced dimensions. Recently, the influence of intrinsic disorder on the Mott metal-to-insulator transition (MIT) has been in the focus of experimental and theoretical studies. Fortunately, the degree of intrinsic disorder can be systematically studied through a structural glass-like transition related to the ethylen-endgroups of the BEDT-TTF molecules.
The common method of choice to study the fundamentals of this transition would be dielectric spectroscopy, which due to the materials’ high conductivity, however, is not applicable.
In this contribution we demonstrate that fluctuation (noise) spectroscopy is a suitable technique to access the intrinsic properties of the glass-like transition. The temperature dependence of 1/f-type fluctuations around this transition can be described by a Vogel-Fulcher-Tamman law. Thereby new insight in the glass-like transition is gained and enables one to classify the κ-(BEDT-TTF)₂X-salts as highly fragile glasses.