Observing vortex motion on NbSe₂ with STM

Highlights: • For the first time we observe vortex motion on a local scale with STM with nanometer resolution. • This technique can be extended to other applications outside superconductivity where detection of fast motion is necessary on the nanometer scale. • The motion of the vortices is along one of the principal axis of the vortex lattice. • We show the power of STM that it can operate at higher magnetic fields than magnetic scanning probe techniques. - Abstract: 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)