Effect of non-magnetic impurities on the gap of a $d_{x^2-y^2}$ superconductor as seen by angle-resolved photoemission

Abstract

An analysis of angle-resolved photoemission (ARPES) experiments in the superconducting state of the high \tc copper-oxides is presented. It is based on a phenomenological weak-coupling BCS model which incorporates the experimental normal state dispersion extracted from ARPES, and non-magnetic impurity scattering in the presence of a $d_{x^2-y^2}$ order parameter (OP). It is shown, that already in the pure case, the broadening by finite momentum resolution of the analyzer leads to a finite region of apparent `gaplessness' around the true node of the OP. Non-magnetic impurities further amplify this effect by introducing additional spectral weight around zero frequency. At sufficiently large impurity concentrations $n_i\approx 0.02-0.05$, this results in an extended region of `gaplessness' up to $\delta \varphi =\pm 7$ ($\varphi$ the angle on the Fermi surface) around the true node for a large range of moderate to strong impurity potential strengths. Different ways to identify the presence of impurity scattering in the ARPES spectra are proposed.

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References in corpus (4)

• Phenomenological Models for the Gap Anisotropy of Bi-2212 as Measured by ARPES
• Direct observation of particle-hole mixing in the superconducting state by angle-resolved photoemission
• Non-magnetic impurities in two dimensional superconductors
• Phenomenological BCS theory of the high-$T_c$ cuprates

Cited by in corpus (5)

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• Inhomogeneous order-parameter suppression in disordered d-wave superconductors
• Details of disorder matter in 2D d-wave superconductors
• Impurity states in multiband s-wave superconductors: analysis of iron pnictides
• Electron Self-Energy of High Temperature Superconductors as Revealed by Angle Resolved Photoemission