Singularity in self-energy and composite fermion excitations of interacting electrons

Article

关键词: IMPURITY ANDERSON MODEL;    MEAN-FIELD THEORY;    RENORMALIZATION-GROUP;    HEAVY FERMIONS;    HUBBARD-MODEL;    TRANSITIONS;    SPECTRA;    SYSTEMS;   

DOI  :  10.1103/PhysRevB.87.085120

来源: SCIE

【 摘 要 】

We study the coherent excitations of a composite fermion operator f(i sigma) (-1)(ni (sigma) over bar), where f(i sigma) is the fermion operator for interacting electrons and n(i (sigma) over bar) is the number operator of electrons with the opposite spin. In the two-impurity Anderson model, we show that the excitation of this composite fermion has a finite spectral weight near the Fermi energy in the regime dominated by intersite spin exchange coupling where the Kondo fixed point is prevented. From scattering off this coherent composite fermion mode, the excitation of the regular fermion f(i sigma) develops a pseudogap and its self-energy is singular. Conversely, when the regular fermion develops Kondo resonance in the Kondo resonance regime, the excitation of the composite fermion develops a pseudogap instead. We argue that the composite fermion could develop a Fermi surface but hidden from charge excitations in lattice generalizations. DOI: 10.1103/PhysRevB.87.085120

【 授权许可】

Free