Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Correlated Electrons: Low-dimensional Systems - Materials 2
TT 28.12: Vortrag
Mittwoch, 28. März 2012, 18:00–18:15, H 0104
Charge-carrier dynamics at the multiferroic transition in the organic charge-transfer salt κ-(ET)2-Cu[N(CN)2]Cl studied by fluctuation (noise) spectroscopy — •Benedikt Hartmann1, Robert Rommel1, 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 (BEDT-TTF)2X are model systems for low-dimensional metals exhibiting both strong electronic correlations and electron-phonon interactions. The quasi-2D triangular lattice Mott insulator κ-(ET)2Cu[N(CN)2]Cl (κ-Cl) undergoes an
antiferromagnetic transition at TN≈27 K. Recently, clear evidence for charge-order driven ferroelectircity coinciding with the onset of magnetic-ordering has been found [1], making κ-Cl a multiferroic material.
We report on fluctuation (noise) spectroscopy, a suitable technique to study the low-frequency charge-carrier dynamics of κ-Cl. We discuss the temperature dependence of the 1/f-type fluctuations in order to get insight in the electronic energy scale involved in the ordering mechanism. We observe deviations of 1/f noise at temperatures around 27 K which may be attributed to the formation of charge-order domains.
P. Lunkenheimer, J. Müller et al., arXiv:1111.2752v2 (2011)