Observing vortex motion on NbSe2 with STM

The resistive state of a superconductor in magnetic field has been thoroughly investigated both by experiments and by theoretical simulations. However, a local study of vortex dynamics inducing dissipation was performed only recently by means of scanning Hall probe microscopy (SHPM). In this work we extend this idea and we visualize the oscillatory motion of vortices in NbSe2 using scanning tunneling microscopy (STM). In contrast to previous experiments, sensitive to magnetic fields, the STM probes the local density of states and the local topography. Its ability to resolve vortices is limited by the coherence length. In the case of type-II superconductors this is expected to resolve vortex motion beyond the detection limit of the SHPM. We experimentally verify the enhanced sensitivity by observing vortex motion in a very dense vortex lattice (H = 600 mT).