The adsorption and dynamics of single indium atoms on a Si(100) surface were studied by means of scanning tunneling microscopy in a temperature range from 30 to 130 K. Single In adatoms are strongly influenced by a tip-surface interaction which is proportional to the tunneling current.
The surface hopping of the In adatoms was recorded and conditions minimizing the tip-surface interaction were investigated. The activation energies and frequency prefactors for thermally activated hopping were calculated from a temperature dependence of lifetimes of In adatoms in adsorption positions.