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TT: Fachverband Tiefe Temperaturen

TT 42: Correlated Electrons: Low-dimensional Systems - Models 2

TT 42.3: Vortrag

Donnerstag, 26. März 2009, 14:30–14:45, HSZ 301

First principles perspective on the microscopic model for Cs₂CuCl₄ — •Kateryna Foyevtsova, Yuzhong Zhang, Harald Jeschke, and Roser Valenti — Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany

We investigate the microscopic model for the frustrated layered antiferromagnet Cs₂CuCl₄ by performing ab initio density functional theory (DFT) calculations and with the help of the downfolding and tight-binding methods. The combination of these methods provide the relevant interaction paths in this material, and we estimate the corresponding exchange constants. We find for Cs₂CuCl₄ that the choice of the structural optimisation scheme within DFT is crucial for the correct evaluation of the exchange constants. We discuss the DFT-derived model by comparing our results with the exchange constants estimated from the neutron scattering data and by analyzing the ability of both theoretical and experimental models to reproduce the measured magnetic properties.