STM Observation of the Abrikosov Flux Lattice and the Density of States near and inside a Fluxoid.

The Abrikosov flux lattice is imaged in NbSe sub 2 by tunneling into the superconduction gap edge with a low temperature scanning tunneling microscope. The tunneling conductance into a single vortex core is strongly peaked at the fermi energy, suggesting the existance of core states or core excitations. As one moves away from the core, this feature evolves into a density of states which is consistent with a BCS superconduction gap.