2014/05/20 by Inna Vishik, Makoto Hashimoto, Vishik, I. M. +7
Physics and Astronomy · Engineering · #Physics of Superconductivity and Magnetism #Superconducting Materials and Applications #Advanced Condensed Matter Physics
paper · pdf · doi:10.48550/arxiv.1405.4961
The momentum dependence of the superconducting gap in the cuprates has been debated, with most experiments reporting a deviation from a simple dx2-y2 form in the underdoped regime and a few experiments claiming that a simple dx2-y2 form persists down to the lowest dopings. We affirm that the superconducting gap function in sufficiently underdoped Bi2Sr2CaCu2O8+δ (Bi-2212) deviates from a simple d-wave form near the antinode. This is observed in samples where doping is controlled only by oxygen annealing, in contrast to claims that this effect is only seen in cation-substituted samples. Moreover, a quasiparticle peak is present at the antinode down to p=0.08, refuting claims that a deviation from a simple d-wave form is a data analysis artifact stemming from difficulty in assessing a gap in the absence of a quasiparticle.