Ground State and Spectral Properties of a Quantum Impurity in d-Wave Superconductors

Abstract

The variational approach of Gunnarsson and Schönhammer to the Anderson impurity model is generalized to study d-wave superconductors in the presence of dilute spin-1/2 impurities. We show that the local moment is screened when the hybridization exceeds a nonzero critical value at which the ground state changes from a spin doublet to a spin singlet. The electron spectral functions are calculated in both phases. We find that while a Kondo resonance develops above the Fermi level in the singlet phase, the spectral function exhibits a low-energy spectral peak below the Fermi level in the spin doublet phase. The origin of such a ``virtual Kondo resonance'' is the existence of low-lying collective excitations in the spin-singlet sector. We discuss our results in connection to recent spectroscopic experiments on Zn doped high-T${}_c$ superconductors.

5 pages, 4figures, revised version

References in corpus (2)

• Kondo effect of impurity moments in d-wave superconductors: Quantum phase transition and spectral properties
• Local Moment Formation in the Superconducting State of a Doped Mott Insulator

Cited by in corpus (5)

• States of Local Moment Induced by Nonmagnetic Impurities in Cuprate Superconductors
• Magnetic-impurity resonance states for different pairing symmetries in twisted bilayer graphene
• Resonance states near a quantum magnetic impurity in single-layer FeSe superconductors with $d$-wave symmetry
• Visualizing Pairing Symmetry in Nematic Superconductors using spin-polarized spectroscopy of magnetic impurities
• Kondo Compensation in a Pseudogap Phase: a Renormalization Group Study