Tunneling Conductance in Normal Metal–High-TC Cuprate Junctions in the Presence of Magnetic Field

The magnetic field responses of the zero-bias conductance peak (ZBCP) in tunneling spectra of high- T C cuprate junctions are studied theoretically. Our calculation is based on the lattice Green's function method and takes the realistic electronic structure of the high- T C cuprate into account. In marked contrast to previous works, it is shown that the critical magnetic field strength H C exists for the splittings of the ZBCP's to be discernible. H C is almost proportional to the product of the magnitude of pair potential, transmissivity of the junction, and the inverse of the Fermi velocity parallel to the interface (1/ v F y ). The calculated H C 's for the hole-doped superconductors are higher than those for electron-doped ones because of relatively large magnitude of pair potential and the small magnitude of v F y originating from peculiar shape of the Fermi surface.