Series expansion analysis of a tetrahedral cluster spin chain
Institut für Theoretische Physik, Technische Universität Braunschweig, 38106 Braunschweig, Germany
Revised: 21 August 2006
Published online: 6 October 2006
Using analytical series expansion by continuous unitary transformations we study the magnetic properties of a frustrated tetrahedral spin- 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, bond-operator theory and other numerical series expansion are provided and convincing agreement is found.
PACS: 75.10.Jm – Quantized spin models / 75.50.Ee – Antiferromagnetics / 02.30.Mv – Approximations and expansions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006