Impact of an oxygen dopant in Bi2Sr2CaCu2O8

Recent scanning tunneling microscopy studies have shown that local nanoscale pairing inhomogeneities are correlated with interstitial oxygen dopants in Bi2 Sr2 CaCu2 O8+ . 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.