Doping effect on pairing symmetry in cuprate superconductors

We have done a series of tricrystal experiments to investigate the doping dependence of pairing symmetry in various hole-doped cuprate superconductors with doping levels ranging from underdoped to overdoped regimes. The results of this work have indicated that the d(x2-y2) pair state is robust against a wide range of doping variation. Our findings underscore the importance of strong on-site Coulomb repulsion in pairing interaction, which favors the d(x2-y2)-wave pairing symmetry over pair states with other symmetries. (c) 2005 Elsevier Ltd. All rights reserved.