Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Correlated Electrons - Poster Session
TT 20.37: Poster
Mittwoch, 28. März 2007, 14:00–17:45, Poster A
Probing the metal-insulator transition in κ−(ET)2Cu2(CN)3 by hydrostatic He-gas pressure experiments — Christian Strack1, Michael Lang1, and •John Schlueter2 — 1Physikalisches Institut, J.W.-Goethe-Universität, Frankfurt/Main, FOR 412 — 2Materials Science Division, Argonne NL, Illinois, USA
The title compound has gained considerable interest from both the theoretical and experimental side, see e.g. [1+2]. It is a Mott-insulator characterized by a triangular lattice with almost perfect magnetic frustration. This leads to the absence of long-range magnetic ordering down to 32 mK, the lowest temperature investigated so far [3]. The system, therefore, is a promising candidate for a quantum spin liquid without symmetry breaking [4], which contrasts with the κ−(ET)2Cu[N(CN)2]Cl salts, where a less strong frustration gives rise to long-range magnetic order of local moments. Both systems become metallic and superconducting under pressure with a similar resistivity profile. Comparative studies of the pressure-induced insulator to metal transition for both compounds thus provide a deep insight into the nature of the correlated electron system and, specifically, the role of magnetism. Using both temperature-dependent resistivity measurements under pressure and pressure sweeps at constant temperatures, the phase diagram of the title compound has been explored. A detailed study of the transition from insulator to metal will be presented.
[1] S. Lee et al. PRL 95, 036403 (2005) [2] E. Ohmichi et al. PRB, Vol. 57, No. 13 [3] Y. Shimizu et al. PRL, Vol. 91,No. 10 (2003) [4] Y. Kurosaki et al. PRB, 95,177001 (2005)