Atomically resolved local variation of the barrier height of the flip-flopmotion of single buckled dimers of Si(100)

The dynamics of the flip-flop motion of single buckled dimers of Si(100) wa s elucidated by locating the tip of a scanning tunneling microscope over a single flip-flopping dimer and measuring the tunneling current (time trace) . Based on a statistical analysis of the time trace, we succeeded in estima ting the activation energy and the energy splitting between the two stable configurations of buckling. Strong de pendence of the dynamics of the flip- Rep motion on the local environment was found: Activation energy differs si gnificantly (directly measured 32 meV, estimated similar to 110 meV) for di mers in different domains.