Low-energy structures in vortex core tunneling spectra in Bi2Sr2CaCu2O8+delta

Scanning tunneling spectroscopy allows us to study the changes in the quasi particle local density of states due to the presence of vortex cores in Bi2 Sr2CaCu2O8+delta (BSCCO). The vortex core spectra are characterized by a ga p-like structure similar to the pseudogap measured above T-c. We also obser ve small spectral structures inside the gap in the vortex cores. The observ ed low-energy structures are weaker than what one expects for localized qua siparticle excitations. (C) 2000 Elsevier Science B.V. All rights reserved.