Single-Atom Manipulation of Co Embedded in Cu(001) Surfaces

Scanning tunneling microscopy (STM) is used to study the STM-tip-induced movement of Co atoms in a diluted Co/Cu(001) surface alloy. By varying the sample temperature from 4 K up to room temperature, we measured the threshold temperature at which an incorporated Co atom can be moved, which is approximately 150 K. We propose that a vacancy-mediated mechanism is responsible for the observed movement, in which vacancies under the tip area exchange with an embedded Co atom. Finally, we present for the first time a selective movement of single Co embedded atoms.