The fabrication of reproducible superconducting scanning tunneling microscope tips

Superconducting scanning tunneling microscope tips have been fabricated wit h a high degree of reproducibility. The fabrication process relies on seque ntial deposition of superconducting Pb and a proximity-coupled Ag capping l ayer onto a Pt/Ir tip. The tips were characterized by tunneling into both n ormal-metal and superconducting films. The simplicity of the fabrication pr ocess, along with the stability and reproducibility of the tips, clear the way for tunneling studies with a well-characterized, scannable superconduct ing electrode. (C) 2001 American Institute of Physics.