The Impact of an Oxygen Dopant in an ideal Bi-2212 Crystal

TL;DR

This study investigates how interstitial oxygen dopants in Bi-2212 crystals influence local electronic and magnetic properties, revealing their role in modifying superconducting and magnetic interactions at the nanoscale.

Contribution

It combines electrostatic and cluster calculations to analyze the local effects of oxygen dopants on electronic structure, magnetic exchange, and lattice interactions in Bi-2212.

Findings

Electrostatic effects increase charge transfer energy locally.

Dopants slightly suppress magnetic exchange J.

Coupling to c-axis phonons is strongly affected near dopants.

Abstract

Recent scanning tunneling microscopy studies have shown that local nanoscale pairing inhomogenities are correlated with interstitial oxygen dopants in Bi-2212. 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 increases the charge transfer energy and slightly suppresses 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 sizable local increase of J. This implies a strong local interplay between antiferromagnetism, polarons, and superconducting pairing.