Functional renormalization group for commensurate antiferromagnets: Beyond the mean-field picture

Article

关键词: HUBBARD-MODEL;    GROUP FLOWS;    SYMMETRIES;    TRANSFORMATIONS;    SYSTEMS;    PHASES;   

DOI  :  10.1103/PhysRevB.90.035140

来源: SCIE

【 摘 要 】

We present a functional renormalization group (fRG) formalism for interacting fermions on lattices that captures the flow into states with commensurate spin-density-wave order. During the flow, the growth of the order parameter is fed back into the flow of the interactions and all modes can be integrated out. This extends previous fRG flows in the symmetric phase that run into a divergence at a nonzero RG scale, i.e., that have to be stopped at the ordering scale. We use the corresponding Ward identity to check the accuracy of the results. We apply our method to a model with two Fermi pockets that have perfect particle-hole nesting. The results obtained from the fRG are compared with those in random-phase approximation.

【 授权许可】

Free