Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.64: Poster

Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B

Magnetic Field Effects on a Quasi-2D Organic Compound Close to the Mott Transition — •Mariano de Souza¹, Andreas Bruehl¹, Christian Strack¹, Bernd Wolf¹, Dieter Schweitzer², and Michael Lang² — ¹Physikalisches Institut, J.W. Goethe-Universität, Max-von-Laue Str. 1, SFB/TRR49, D-60438 Frankfurt am Main, Germany — ²3.Physikalisches Institut, Universität Stuttgart, D-70550 Stuttgart, Germany

Organic charge-transfer salts of the κ-phase(BEDT-TTF)₂X family have been the subject of intensive research in the field of strongly correlated electron systems over the last few years. In this contribution, we present high-resolution directional dependent dilatometry studies under magnetic fields on the fully deuterated X=Cu[N(CN)₂]Br salt, recognized to be situated close to the Mott metal-insulator (MI) transition [1]. Our findings reveal the insensitivity of the Mott MI transition temperature under fields up to 10 T, which is in accordance with the proposal of a Mott insulating state with a hole localized on a dimer. For fields along the interlayer b-axis, a field-induced (FI) phase transition at T_FI=9.5 K is observed. The latter is discussed in terms of a spin-flop transition with strong magneto-elastic coupling accompanied by a suppression of percolative superconductivity for magnetic fields above 1 T. [1] M. de Souza, A. Brühl, Ch. Strack, B. Wolf, D. Schweitzer, and M. Lang, Phys. Rev. Lett. 99, 037003 (2007).