Scanning tunneling spectroscopy of the vortex state in NbSe2 using a superconducting tip

The vortex electronic structure in the multiband superconductor NbSe2 is studied by means of scanning tunneling spectroscopy (STS) using a superconducting tip. The use of a superconducting tip (Pb) as a probe provides an enhancement of the different features related to the DOS of NbSe2 in the tunneling conductance curves. This use allows the observation of rich patterns of electronic states in the conductance images around the vortex cores in a wide range of temperature, as well as the simultaneous acquisition of Josephson current images in the vortex state.