Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 11: CE: Low-dimensional Systems - Materials 2

TT 11.4: Vortrag

Dienstag, 23. März 2010, 10:15–10:30, H18

Ground state description of BiCu₂PO₆ and BiCu₂AsO₆ — •Deepa Kasinathan, Alexander Tsirlin, Oleg Janson, and Helge Rosner — Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

Low dimensional spin systems have always been of interest to the physics community due to their inherent exotic magnetic properties. A further impetus for the study of low-dimensional spin systems was given by the discovery of spin-ladder materials, due to the fact that they are intermediate objects between 1D and 2D systems. Recent experiments by two groups [1,2] on a spin-ladder material BiCu₂PO₆ exhibited a gapped singlet ground state with a spin gap of about 34 K, though the strength of the spin-exchange interactions have remained controversial. No consensus has been reached on the correct spin-ladder model to describe this compound. We will report on our re-investigations of BiCu₂PO₆ and the related material BiCu₂AsO₆ using density functional theory based electronic structure calculations and as well as Transfer Matrix Renormalization Group (TMRG) calculations. Our results necessitate the inclusion of previously neglected exchange couplings to describe the spin-ladder model more appropriately.

[1] B. Koteswararao, et. al., Phys. Rev. B 76, 052402 (2007).

[2] O. Mentré, et. al., Phys. Rev. B 80, 180413 (2009).