Robust dx2-y2 pairing symmetry in hole-doped cuprate superconductors -: art. no. 187004

Although initially quite controversial, it is now widely accepted that the Cooper pairs in optimally doped cuprate superconductors have predominantly d(x2-gamma2) wave function symmetry, and the controversy has now shifted to whether the pairing symmetry changes away from optimal doping. Here we present phase-sensitive tricrystal experiments on three cuprate systems: Y0.7Ca0.3Ba2Cu3O7-delta (Ca-doped Y-123), La2-xSrxCuO4 (La-214), and Bi2Sr2CaCu2O8+delta (Bi-2212), with doping levels covering the underdoped, optimal, and overdoped regions. Our work implies that predominantly d(x2-y2) pairing symmetry is robust over a large variation in doping.