Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.74: Poster

Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B

The influence of the inter-chain coupling on the spiral ground state of the frustrated quasi-one-dimensional spin-half Heisenberg magnet — •ronald zinke¹, stefan-ludwig drechsler², and johannes richter¹ — ¹Institut für theoretische Physik, Universität Magdeburg, PO Box 4120 — ²Leibnitz-Institut für Festkörper- und Werkstoffforschung (IWF) D-01171 Dresden, P.O. Box 270116

Recent investigations on edge-shared chain cuprates such as LiCuVO₄, NaCu₂O₂ or Li₂ZrCuO₄ have identified these materials as quasi-one-dimensional frustrated quantum helimagnets with an incommensurate spiral ground state. While strictly one-dimensional frustrated quantum magnets have been widely studied theoretically, the role of the experimentally relevant inter-chain couling J_⊥ on the spiral ground state has not been discussed so far.
We perform coupled cluster method (CCM) calculations for coupled frustrated spin-1/2 J₁-J₂-chains. We consider different signs for the exchange interactions J₁ and J_⊥ this way realizing frustrated ferro- as well as antiferromgnets. We study the influence of quantum fluctuations and of the interchain coupling J_⊥ on the position of the transition from the commensurate collinear to the incommensurate spiral ground state and on the pitch angle θ. We find that not only the transition point but also the nature of the transition (first order/second order) depends on the strength of quantum fluctuations.