Spectral properties of a quantum impurity in d-wave superconductors

Xi Dai; Ziqiang Wang

doi:10.1103/PhysRevB.67.180507

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Spectral properties of a quantum impurity in d-wave superconductors

Xi Dai, Ziqiang Wang

DOI 10.1103/PhysRevB.67.180507 · Physical Review B

T1

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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-12 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-Tc superconductors.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown