Symmetry of the Gap in Bi2212 from Photoemission Spectroscopy

TL;DR

This paper reanalyzes photoemission spectroscopy data on Bi2212, challenging previous interpretations of a d-wave superconducting gap and proposing that the data are better explained by an anisotropic s-wave gap.

Contribution

It demonstrates that aging-related spectral changes in Bi2212 are inconsistent with a d-wave gap but align with an anisotropic s-wave gap, revising previous conclusions.

Findings

Data inconsistent with d-wave symmetry after aging

Spectral changes compatible with anisotropic s-wave gap

Revised understanding of gap symmetry in Bi2212

Abstract

In a recent Letter, Shen et al have detected a large anisotropy of the superconducting gap in Bi2212, consistent with d-wave symmetry, from photoemission spectroscopy. Moreover, they claim that the change in their spectra as a function of aging is also consistent with such an intrepretation. In this Comment, I show that the latter statement is not entirely correct, in that the data as a function of aging are inconsistent with a d-wave gap but are consistent with an anisotropic s-wave gap.