Relating STM, ARPES, and Transport in the Cuprate Superconducting State

TL;DR

This paper synthesizes various experimental data to show that the superconducting state in optimally doped BSCCO-2212 aligns with BCS theory incorporating a d-wave gap and small-angle scattering, explaining differences with YBCO.

Contribution

It provides a unified interpretation of STM, ARPES, and transport data, highlighting the role of small-angle scattering in cuprate superconductors.

Findings

Superconducting state described by BCS with d-wave gap

Small-angle scattering explains differences between BSCCO and YBCO

Nanoscale inhomogeneity observed in local gap edge

Abstract

We discuss a wealth of data from various types of experiments which together suggest that the superconducting state of optimally to overdoped BSCCO-2212 can be well-described by the BCS theory with a d-wave gap together with small-angle scattering from out-of-plane defects. These include scanning tunnelling Fourier transform spectroscopy observation of nanoscale inhomogeneity in the local gap edge position, the narrowing of the antinodal ARPES spectrum when BSCCO becomes superconducting, as well as the behavior of the microwave and thermal conductivities. We suggest that the large amount of small-angle scattering in BSCCO can account for the differences between the superconducting properties of BSCCO and YBCO.