Strong-coupling analysis of scanning tunneling spectra in Bi$_2$Sr$_2$Ca$_2$Cu$_3$O$_{10+\delta}$

TL;DR

This paper analyzes scanning tunneling spectra in optimally-doped Bi-2223 superconductors using a strong-coupling model that incorporates band structure, BCS gap, and electron-spin resonance interactions, providing detailed parameter fits and simulations.

Contribution

It introduces a comprehensive strong-coupling fitting approach for tunneling spectra in Bi-2223, including parameter extraction and comparison with ARPES data.

Findings

Parameters vary with gap magnitude

Strong-coupling effects are significant in spectra

Simulated ARPES spectra agree with experiments

Abstract

We study a series of spectra measured in the superconducting state of optimally-doped Bi-2223 by scanning tunneling spectroscopy. Each spectrum, as well as the average of spectra presenting the same gap, is fitted using a strong-coupling model taking into account the band structure, the BCS gap, and the interaction of electrons with the spin resonance. After describing our measurements and the main characteristics of the strong-coupling model, we report the whole set of parameters determined from the fits, and we discuss trends as a function of the gap magnitude. We also simulate angle-resolved photoemission spectra, and compare with recent experimental results.