Doping effect on pairing symmetry in cuprate superconductors

Abstract 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 x 2 − y 2 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 x 2 − y 2 -wave pairing symmetry over pair states with other symmetries.