Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 58: Transport: Poster Session
TT 58.34: Poster
Mittwoch, 9. März 2016, 15:00–18:30, Poster D
Origin of the Glasslike Dynamics in Molecular Conductors κ-(BEDT-TTF)2X — •Benedikt Hartmann1, Robert Rommel1, Jens Brandenburg1, Steve M. Winter1, John Schlueter2, Takahiko Sasaki3, and Jens Müller1 — 1Institute of Physics, Goethe-University Frankfurt, Frankfurt (M), Germany — 2Argonne National Laboratory, Materials Science Division, Argonne (IL), USA — 3Institute for Materials Research, Tohoku University, Sendai, Japan
The organic molecular conductors κ-(BEDT-TTF)2X exhibit a structural glasslike transition, which can be utilized (i) to modify the correlation strength of the charge carriers close to the Mott metal insulator transition [1], as well as (ii) to study the influence of intrinsic molecular disorder [2]. A deeper microscopic understanding, however, has been lacking. In this contribution we demonstrate that fluctuation (noise) spectroscopy is an effective technique to access the intrinsic properties of the glasslike transition [3]. The temperature dependence of 1/f-type fluctuations can be described by a Vogel-Fulcher-Tamman law,
allowing to classify the κ-(BEDT-TTF)2X-salts as highly fragile orientational glasses. Heat pulse experiments and supporting ab initio calculations provide an explanation for the origin of the observed glassy dynamics in κ-(BEDT-TTF)2X in terms of a simple two-level model, making quantitative statements possible and predictions for the occurrence of glassiness in different κ-(BEDT-TTF)2X systems feasible [3].
B. Hartmann et al., PRL 114, 216403
B. Hartmann et al., PRB 90, 195150
J. Müller et al., NJP 17, 083057