PROBING THE LOCAL-EFFECTS OF MAGNETIC-IMPURITIES ON SUPERCONDUCTIVITY

The local effects of isolated magnetic adatoms on the electronic prope rties of the surface of a superconductor were studied with a low-tempe rature scanning tunneling microscope. Tunneling spectra obtained near magnetic adsorbates reveal the presence of excitations within the supe rconductor's energy gap that can be detected over a few atomic diamete rs around the impurity at the surface, These excitations are locally a symmetric with respect to tunneling of electrons and holes, A model ca lculation based on the Bogoliubov-de Gennes equations can be used to u nderstand the details of the local tunneling spectra.