Evidence of Doping-Dependent Pairing Symmetry in Cuprate Superconductors

الأصل · EN

Scanning tunneling spectroscopy (STS) studies reveal long-range spatial homogeneity and predominantly dₓ₂₋y₂-pairing spectral characteristics in under- and optimally doped YBa₂Cu₃O₇₋δ superconductors, whereas STS on YBa₂(Cu₀.₉₉₃₄Zn₀.₀₀₂₆Mg₀.₀₀₄)₃O₆.₉ exhibits microscopic spatial modulations and strong scattering near the Zn or Mg impurity sites, together with global suppression of the pairing potential. In contrast, in overdoped (Y₀.₇Ca₀.₃)Ba₂Cu₃O₇₋δ, (dₓ₂₋y₂+s)-pairing symmetry is found, suggesting significant changes in the superconducting ground-state at a critical doping value.