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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.104: Poster

Wednesday, March 29, 2006, 14:30–18:30, P1

Series expansion analysis of a tetrahedral cluster spin chain — •Marcelo Arlego and Wolfram Brenig — Institute for Theoretical Physics, Technical University of Braunschweig, Germany

Using series expansion by continuous unitary transformations we study the zero temperature magnetic properties of a frustrated tetrahedral spin-1/2 chain. Starting from the limit of isolated tetrahedra we analyze the evolution of the ground state energy and the elementary triplet dispersion as a function of the inter-tetrahedral coupling. The quantum phase diagram is evaluated and is shown to incorporate a singlet product, a dimer, and a Haldane phase. Comparison of our results with those from several other techniques, such as density matrix renormalization group, exact diagonalization and bond-operator mean field theory are provided and convincing agreement is found.