NANOMETER-SCALE PATTERNS ETCHED INTO SUPERCONDUCTING NBSE2 WITH AN STM AT 4.2-K

We show that nanometer scale structures can be etched into the layered superconductor NbSe2 with an STM tip, and that small dots can he depo sited afterwards. Etching only takes place for tunneling resistances l ess than or equal to 5 - 10 M Ohm, and can both he performed at room t emperature and at He temperature. This indicates that not 'chemical' b ut 'mechanical' tip-sample interaction, combined with weak binding of layers, is responsible for removal of the atoms. Since the superconduc ting gap and vortices can be imaged as well, it is possible to study t he interaction between superconductivity and artificially produced def ects.