| We apply the Functional Renormalization Group to describe the phase diagrams of spin-½ Heisenberg antiferromagnets on two dimensional lattices. In order to be able to perform diagrammatic approximations we rewrite the spin operators in terms of auxiliary fermions. It turns out that the inclusion of certain three-particle vertices in the form proposed by Katanin is essential to describe the phase diagrams correctly. Calculating the magnetic susceptibility and the spin-spin correlations we are able to distinguish between magnetically ordered and paramagnetic phases. In particular, we are interested in the melting of magnetic long-range order as an effect of frustration. Thereby we focus on the J1-J2-model as well as on Heisenberg models on a triangular, honeycomb and Kagome lattice. Furthermore, anisotropic spin interactions are considered. We find phase diagrams in good agreement with numerical studies. |
|