Inhomogeneity Induces Resonance Coherence Peaks in Superconducting BSCCO

TL;DR

This study uses scanning tunneling spectroscopy to reveal how inhomogeneity in BSCCO superconductors creates resonance coherence peaks, indicating coexisting phases with different gap characteristics.

Contribution

It introduces a phenomenological model linking local inhomogeneity to resonance coherence peaks in the electronic density of states.

Findings

Identification of patches with distinct gap sizes and coherence peaks.

Correlation between inhomogeneity and resonance coherence peaks.

Support for a model of embedded regions with varying gap amplitudes.

Abstract

In this paper we analyze, using scanning tunneling spectroscopy, the density of electronic states in nearly optimally doped BSCCO in zero field. Focusing on the superconducting gap, we find patches of what appear to be two different phases in a background of some average gap, one with a relatively small gap and sharp large coherence peaks and one characterized by a large gap with broad weak coherence peaks. We compare these spectra with calculations of the local density of states for a simple phenomenological model in which a 2 xi_0 * 2 xi_0 patch with an enhanced or supressed d-wave gap amplitude is embedded in a region with a uniform average d-wave gap.