Nanoscale superconducting properties of amorphous W-based deposits grown with a focused-ion-beam

We present very low temperature scanning tunneling microscopy and spectroscopy (STM/S) measurements in W-based amorphous superconducting nanodeposits grown using a metal–organic precursor and a focused-ion-beam. The superconducting gap closely follows s-wave Bardeen–Cooper– Schrieffer theory, and STS images under magnetic fields show a hexagonal vortex lattice whose orientation is related to features observed in the topography through STM. Our results demonstrate that the superconducting properties at the surface of these deposits are very homogeneous, down to atomic scale.