Vertical Manipulation of Individual Atoms by a Direct STM Tip-Surface Contact on Ge(111)

Abstract
A new type of vertical manipulation with the scanning tunneling microscope (STM), involving only direct STM tip-surface contact at zero bias voltage, is used to extract, in a very controlled manner, individual germanium atoms from a Ge(111) surface. The duration of the extraction mechanism is found to be surprisingly long, of the order of 10 ms. To explain these effects, a complete calculation of the STM tip approach and retraction sequence is performed by optimizing the total junction geometry at each step.