Mapping the superconducting condensate surrounding a vortex in superconducting V3Si using a superconducting MgB2 tip in a scanning tunneling microscope
Résumé
As shown recently [Proslier , Europhys. Lett. 73, 962 (2006)], it is possible to map the superconducting (SC) condensate by measuring locally the Josephson tunneling current. We apply this technique to image the vortex lattice in V3Si which is used as the simplest example of a spatially varying quantum condensate. The Josephson scanning tunneling microscope (JSTM) maps revealed the vortex lattice with the Josephson effect being present outside the vortices and disappearing progressively toward the vortex core. The characteristic length scales of a vortex observed in the Josephson regime are compared to the ones obtained in the quasiparticle regime. We demonstrate that the JSTM allows a nanometer scale resolution of the SC condensate that may be applied to inhomogeneous phases such as high-T-c superconductors.