Mono-atomic tips for scanning tunneling microscopy

Abstract

By field-ion microscopy techniques, we have been able to create stable tips whose very ends are made up of just one individual atom, deposited from the gas phase onto an upper terrace of a pyramidal (111)-oriented tungsten tip. The first three layers of the tip consist of one, three, and seven atoms, respectively. Consequences of these observations for the understanding of energy transfer between gas-phase atoms and a solid surface are also discussed.