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TT: Fachverband Tiefe Temperaturen

TT 18: Correlated Electrons: Low-dimensional Systems - Materials 2

TT 18.3: Vortrag

Dienstag, 26. Februar 2008, 15:45–16:00, H 2053

First principles study of the charge transfer salt κ-(BEDT-TTF)₂Cu(CN)₃ — •Harald O. Jeschke, Hem C. Kandpal, and Roser Valenti — Institut für Theoretische Physik, Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt, Germany

The charge transfer salt κ-(BEDT-TTF)₂Cu(CN)₃ has attracted a lot of attention due to experimental evidence that it is a realization of a spin liquid: no magnetic ordering was found down to 20 mK [1]. For a good description of this behaviour, it is crucial to consider the appropriate effective model for this system. Here, we present electronic structure calculations in the frame of density functional theory (DFT) and derive an effective model with the NMTO (N-th order muffin tin orbital) downfolding method and discuss its features. Since from X-ray diffraction, the structure of κ-(BEDT-TTF)₂Cu(CN)₃ has been determined without hydrogen positions, we first prepare a very similar structure including hydrogen atoms and carefully relax it using the projector augmented wave method. This structure is then used for the DFT and NMTO analysis.

[1] S. Ohira, Y. Shimizu, K. Kanoda and G. Saito, J. Low Temp. Phys. 142, 153 (2006).