Tunneling investigations of single crystals of the singlelayer cuprate Bi2Sr2CuOz in high magnetic fields

The coexistence of a superconducting gap and a normal-state gap (pseudogap) is observed in tunneling experiments with high-quality single crystals of the single-layer cuprate Bi2Sr2CuOz. At temperatures T < T-c the normal-state gap, whose width is close to that of the superconducting gap, does not vanish in magnetic fields H > H-c2. The large smearing of the gap structure in the tunneling spectra and the high conductance of tunnel junctions at zero bias voltage are due to the strong angular dependence of the superconducting- and normal-state gaps. The results of the investigations are in good agreement with recently published angle-resolved photoemission data. (C) 1998 American Institute of Physics.