Single Atom Electron Emission from the Silicon Tip Coated by Calcium Fluoride with Samarium Dopant Ions V.N. Konopsky, S.K. Sekatskii et V.S. Letokhov J. Phys. IV France, 06 C5 (1996) C5-125-C5-128 DOI: 10.1051/jp4:1996520