Impact of an oxygen dopant in Bi₂Sr₂CaCu₂O₈₊

¹  Department of Physics, University of Waterloo - Waterloo, Ontario, N2L 3G1, Canada
²  Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
³  Geballe Laboratory for Advanced Materials, Stanford University - Stanford, CA, 94305, USA
⁴  Paul Scherrer Institut, Condensed Matter Theory Group - Villigen PSI, Switzerland

Corresponding author: tpd@stanford.edu

Received: 27 December 2008
Accepted: 8 April 2009

Abstract

Recent scanning tunneling microscopy studies have shown that local nanoscale pairing inhomogeneities are correlated with interstitial oxygen dopants in Bi₂Sr₂CaCu₂O₈₊. Combining electrostatic and cluster calculations, in this paper the impact of a dopant on the local Madelung and charge transfer energies, magnetic exchange J, Zhang-Rice mobility and interactions with the lattice is investigated. It is found that electrostatic modifications locally increase the charge transfer energy and slightly suppress J. It is further shown that coupling to c-axis phonons is strongly modified near the dopant. The combined effects of electrostatic modifications and coupling to the lattice yield broadened spectral features, reduced charge gap energies and a sizeable local increase of J. This implies a strong local interplay between antiferromagnetism, polarons and superconducting pairing.