Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 19: Correlated Electrons: Low-dimensional Materials

TT 19.5: Vortrag

Dienstag, 28. März 2006, 15:00–15:15, HSZ 301

A possible dimerized ground state in the spin-1/2 cuprate Na₃Cu₂SbO₆ — •Miriam Schmitt¹ and Helge Rosner² — ¹TU Dresden — ²MPI CPfS Dresden

Simulated by the resent discovery of helical ground states in spin-1/2 chain cuprates, we present an electronic structure study of the newly synthesized compound Na₃Cu₂SbO₆. This compound contains Cu₂O₆ sub-units build from edge shared CuO₂ plaquettes. The Cu₂O₆ sub-units are arranged in chains along the y-direction, interrupted by SbO₆ octahedra. The Cu-O-Cu bond angle in the Cu₂O₆ units is about 95^∘, therefore a competition of ferromagnetic and antiferromagnetic interactions can be expected. We investigate the electronic and magnetic structure of Na₃Cu₂SbO₆ starting from LDA band structure calculations that are mapped to an effective one-band tight-binding model and subsequently to an extended Heisenberg model. A variety of possible ground states is compared with respect to their total energy including the strong correlation using the LDA+U scheme. Furthermore, we discuss frustration of the magnetic exchange interaction along the chains due to next-nearest neighbor coupling and the influence of inter-chain interaction.
supported by the DFG ( Emmy-Noether-program)