Abstract Submitted for the MAR10 Meeting of The American Physical Society Strong coupling picture of superconductivity in underdoped cuprates II: quasi-particle gap and its symmetry1

Submitted for the MAR10 Meeting of The American Physical Society Strong coupling picture of superconductivity in underdoped cuprates II: quasi-particle gap and its symmetry1 WEI KU, YUCEL YILDIRIM, CMPMS, Brookhaven National Lab — Recent observations of quasiparticle superconducting gap via ARPES and STM revealed important clues to the nature of superconductivity in the underdoped cuprates. Here, we study the quasiparticle gap theoretically in the presence of a larger pseudo-gap, within the strong coupling limit. Without any free parameter, the resulting quasi-particle gap is found to agree very well with the experimental observations. Most surprisingly, at very low doping, the symmetry is found to deviate significantly from the simple d-wave shape of the order parameter. In contrast to the Bogoliubov excitation, a new interpretation of the nature of the quasi-particles at the edge of the gap will be presented that is more suitable for the strong coupling region. 1supported by DOE and DOE-CMSN Wei Ku CMPMS, Brookhaven National Laboratory Date submitted: 20 Nov 2009 Electronic form version 1.4