Renormalization group analysis of magnetic and superconducting instabilities near van Hove band fillings

[摘要] Phase diagrams of the two-dimensional one-band t-t' Hubbard model are obtained within the two-patch and temperature-cutoff many-patch renormalization group approaches. At small t' and at van Hove band fillings antiferromagnetism dominates, while with increasing t' or changing filling antiferromagnetism is replaced by d-wave superconductivity. Near t' = t/2 and close to van Hove band fillings the system is unstable towards ferromagnetism. Away from van Hove band fillings this ferromagnetic instability is replaced by a region with dominating triplet p-wave superconducting correlations. The results of the renormalization-group approach are compared with the mean-field results and the results of the T-matrix approximation.

[发布日期] 2003-11-01

[关键词] 2-DIMENSIONAL HUBBARD-MODEL;WAVE SUPERCONDUCTIVITY;CORRELATED ELECTRONS;SPIN FLUCTUATIONS;NEAREST-NEIGHBOR;PHASE-SEPARATION;FERMI-SURFACE;2 DIMENSIONS;FERROMAGNETISM;SR2RUO4