Vortex Imagine in the w-Band of Magnesium Diboride

M. R. Eskildsen, M. Kugler, S. Tanaka, J. Jun, S. M. Kazakov, J. Karpinski, and O. Fischer
Abstract:

We report scanning tunneling spectroscopy imagine of the vortex lattice in single crystalline MgB2. By tunneling parallel to the c-axis, a single superconducting gap (=2.2 meV) associated with the -band is observed. The vortices in the -band have a large core size compared to estimates based on Hc2 , and show an absence of localized states in the core. Furthermore, superconductivity between, the vortices is rapidly suppressed by an applied field. These result suggest that superconductivity in the -band is, at least partially, induced by the intrinsically superconducting -bind.