We have used scanning tunneling spectroscopy to investigate short-length electronic correlations in three-layer Bi2Sr2Ca2Cu3O(10+d) (Bi-2223). We show that the superconducting gap and the energy Omega_dip, defined as the difference between the dip minimum and the gap, are both modulated in space following the lattice superstructure, and are locally anti-correlated. Based on fits of our data to a microscopic strong-coupling model we show that Omega_dip is an accurate measure of the collective mode energy in Bi-2223. We conclude that the collective mode responsible for the dip is a local excitation with a doping dependent energy, and is most likely the (pi,pi) spin resonance.
@article{arxiv.0909.0500,
title = {Imaging the essential role of spin-fluctuations in high-Tc superconductivity},
author = {N. Jenkins and Y. Fasano and C. Berthod and I. Maggio-Aprile and A. Piriou and E. Giannini and B. W. Hoogenboom and C. Hess and T. Cren and Ø. Fischer},
journal= {arXiv preprint arXiv:0909.0500},
year = {2009}
}