Spectral properties of a quantum impurity in d-wave superconductors

Article

关键词: CE COMPOUNDS;    STATES;    MOMENTS;    PROBE;    MODEL;   

DOI  :  10.1103/PhysRevB.67.180507

来源: SCIE

【 摘 要 】

The variational approach of Gunnarsson and Schonhammer 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 with recent spectroscopic experiments in Zn-doped high-T-c superconductors.

【 授权许可】

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