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TT: Fachverband Tiefe Temperaturen

TT 7: Correlated Electrons: Spin Systems, Itinerant Magnets 1

TT 7.7: Talk

Monday, March 11, 2013, 11:15–11:30, H19

Non-perturbative RG approach to frustrated magnets — •Nils Hasselmann¹ and Andreas Sinner² — ¹Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart — ²Institut für Physik, Theorie II, Universität Augsburg, 86135 Augsburg

Frustrated magnets support in two dimensions topological defects which for Heisenberg models are point-like and of Z₂ character. We analyse, using a Ginzburg-Landau-Wilson formulation and a non-local approximation of the interaction, frustrated magnets within the non-perturbative renormalization group approach. At low temperatures we recover the predictions of the usual non-linear sigma-model theory for frustrated magnets. However, in contrast to the usual non-linear sigma-model approach, but in agreement with Monte-Carlo simulations, we find in our approach clear signs of a defect unbinding transition at finite temperatures in frustrated Heisenberg models.