Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 8: Correlated Electrons: Spin Systems and Itinerant Magnets 1

TT 8.9: Vortrag

Montag, 25. Februar 2008, 16:15–16:30, H 0104

Impurity induced spin textures in quantum antiferromagnets — •Julian Engel and Stefan Wessel — Institute for Theoretical Physics III, Stuttgart University, Germany

We present results from quantum Monte Carlo studies on the effects of a magnetic impurity on the order parameter distribution in a two-dimensional host antiferromagnet. We find that for a weak coupling to the impurity spin, the staggered magnetization is enhanced throughout the lattice, whereas increasing the coupling between the host and the impurity spin restricts this enhancement to the close vicinity of the impurity, whereas on all other sites the staggered magnetization gets suppressed compared to the clean case. Approaching the limit of an infinite coupling between host and impurity, the system hence crosses over to the case of an embedded non-magnetic impurity site. We compare our results with previous findings, based on spin-wave and perturbation theory.