Magnetic field dependence of the superconducting energy gap in Bi2Sr2CaCu2O8+δ probed using break-junction tunneling spectroscopy

The magnetic-field-dependent in-plane tunneling conductance dI/dV(V) on the Bi2Sr2CaCu2O8+delta single crystals has been investigated using break junctions. In contrast to previous tunneling measurements of Bi2212, where the position of the gap peak in dI/dV(V) remained almost unchanged in the applied magnetic fields, our data present evidence that the magnetic field suppresses the superconducting gap in Bi2212. The behavior of a dip-hump structure in tunnel spectra indicates that the magnetic field acts differently on the gap and pseudogap and suggests that the pseudogap does not correlate with the existence of a superconducting gap.