Scanning tunneling spectroscopy measurements on the high temperature superconductor Bi2Sr2CaCu2O8+δ have reported an enhanced spectral gap in the neighborhood of O dopant atoms. We calculate, within density functional theory (DFT), the change in electronic structure due to such a dopant. We then construct and discuss the validity of several tight binding (TB) fits to the DFT bands with and without an O dopant. With the doping-modulated TB parameters, we finally evaluate the spin susceptibility and pairing interaction within spin fluctuation theory. The d-wave pairing eigenvalues are enhanced above the pure system without O dopant, supporting the picture of enhanced local pairing around such a defect.
@article{arxiv.1006.2014,
title = {Modulation of pairing interaction in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ by an O dopant: a density functional theory study},
author = {Kateryna Foyevtsova and H. C. Kandpal and Harald O. Jeschke and S. Graser and H. -P. Cheng and Roser Valentí and P. J. Hirschfeld},
journal= {arXiv preprint arXiv:1006.2014},
year = {2010}
}