  Using a non-contact atomic force microscope we track and manipulate the
position of single electrons confined to atomic structures engineered from
silicon dangling bonds (DBs) on the hydrogen terminated silicon surface. By
varying the probe-sample separation we mechanically manipulate the equilibrium
position of individual surface silicon atoms and use this to directly switch
the charge state of individual DBs. Because this mechanism is based on short
range interactions and can be performed without applied bias voltage, we
maintain both site-specific selectivity and single-electron control. We extract
the short range forces involved with this mechanism by subtracting the long
range forces acquired on a dimer vacancy site. As a result of relaxation of the
silicon lattice to accommodate negatively charged DBs we observe charge
configurations of DB structures that remain stable for many seconds at 4.5 K.
Subsequently we use charge manipulation to directly prepare the ground state
and metastable charge configurations of DB structures composed of up to six
atoms.

Mesoscale and Nanoscale Physics