Interplay of quantum magnetic and potential scattering around Zn or Ni impurity ions in superconducting cuprates

Abstract

To describe the scattering of superconducting quasiparticles from non-magnetic (Zn) or magnetic (Ni) impurities in optimally doped high T${}_c$ cuprates, we propose an effective Anderson model Hamiltonian of a localized electron hybridizing with $d_{x^2-y^2}$-wave BCS type superconducting quasiparticles with an attractive scalar potential at the impurity site. Due to the strong local antiferromagnetic couplings between the original Cu ions and their nearest neighbors, the localized electron in the Ni-doped materials is assumed to be on the impurity sites, while in the Zn-doped materials the localized electron is distributed over the four nearest neighbor sites of the impurities with a dominant $d_{x^2-y^2}$ symmetric form of the wave function. With Ni impurities, two resonant states are formed above the Fermi level in the local density of states at the impurity site, while for Zn impurities a sharp resonant peak below the Fermi level dominates in the local density of states at the Zn site, accompanied by a small and broad resonant state above the Fermi level mainly induced by the potential scattering. In both cases, there are no Kondo screening effects. The local density of states and their spatial distribution at the dominant resonant energy around the substituted impurities are calculated for both cases, and they are in good agreement with the experimental results of scanning tunneling microscopy in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ with Zn or Ni impurities, respectively.

24 pages, Revtex, 8 figures, submitted to Physical Review B for publication. Sub-ject Class: Superconductivity; Strongly Correlated Electrons

References in corpus (5)

• Interplay of magnetism and high-Tc superconductivity at individual Ni impurity atoms in Bi2Sr2CaCu2O8+d
• Kondo effect of impurity moments in d-wave superconductors: Quantum phase transition and spectral properties
• Kondo effect in d-wave superconductors
• Multichannel pseudogap Kondo model: Large-N solution and quantum-critical dynamics
• Local Quasiparticle States near a Unitary Impurity with Induced Magnetic Moment in a d-Wave Superconductor

Cited by in corpus (7)

• Defects in correlated metals and superconductors
• Impurity and interface bound states in $d_{x^2-y^2}+i{d}_{xy}$ and $p_x+i{p}_y$ superconductors
• Microscopic origin of local moments in a zinc-doped high-$T_c$ superconductor
• Phase diagram of a d-wave superconductor with Anderson impurities
• Zero temperature phase diagram of a d-wave superconductor with Anderson impurities
• Effect of impurity states on the NMR spectra of high-$T_c$ cuprates
• Defect and anisotropic gap induced quasi-one-dimensional modulation of local density of states in YBa${}_2$Cu${}_3$O${}_{7-\delta }$