Order-parameter symmetries for magnetic and superconducting instabilities: Bethe-Salpeter analysis of functional renormalization-group solutions

Article

关键词: 2-DIMENSIONAL HUBBARD-MODEL;    DIMENSIONAL FERMI-SURFACE;    WAVE SUPERCONDUCTIVITY;    SPIN FLUCTUATIONS;    SR2RUO4;    FERROMAGNETISM;    TRIPLET;   

DOI  :  10.1103/PhysRevB.72.205128

来源: SCIE

【 摘 要 】

The Bethe-Salpeter equation is combined with the temperature-cutoff functional renormalization group approach to analyze the order parameter structure for the leading instabilities of the 2D t-t(') Hubbard model. We find significant deviations from the conventional s-, p-, or d-wave forms, which is due to the frustration of antiferromagnetism at small and intermediate t('). With adding a direct antiferromagnetic spin-exchange coupling the eigenfunctions in the particle-hole channel have extended s-wave form, while in the particle-particle singlet pairing channel a higher angular momentum component arises besides the standard d(x)(2)-y(2) wave component, which flattens the angular dependence of the gap. For t(') closer to t/2 we find a delicate competition of ferromagnetism and triplet pairing with a nontrivial pair-wavefunction.

【 授权许可】

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