Abstract
Tunneling measurements have been carried out on heavily underdoped and slightly overdoped Bi2Sr2CaCu2O8 + x (Bi2212) single crystals by using a break-junction technique. We find that in-plane tunneling spectra below Tc are the combination of incoherent part from the pseudogap and coherent quasiparticle peaks. There is a correlation between the magnitude of the pseudogap and the magnitude of the superconducting gap in Bi2212. We find that the quasiparticle conductance peaks are caused by condensed soliton-like excitations.