Discriminating the superconducting gap from the pseudogap in Bi(2)Sr(2)CaCu(2)O(8+delta) by interlayer tunneling spectroscopy

Tunneling spectroscopy using a very thin stack of intrinsic Josephson junctions has revealed that the superconducting gap is definitely different from the pseudogap in the Bi(2)Sr(2)CaCu(2)O(8+delta) system. In the underdoped region, the conductance peak arising from the superconducting gap is independently observed in the dI/dV-V curve and its position is much lower than that of the pseudogap. Near the optimum doping level and in the overdoped region, both peaks are located in close proximity. These findings are in conflict with a previous understanding of the pseudogap.