Time-Fluctuation of the Dimer Structure on a Ge(001) Surface Studied by a Monte Carlo Simulation and a First-Principles Calculation

The time-resolving dynamical Monte Carlo simulations (TDMCS) on Ge(001) surface at 200 K for the orientational arrangement at finite temperature are performed. The model potential for the continuous values of the tilting angles are obtained. The coefficients in the model potential are obtained from results of the first-principles calculations. The transition rates of the dimer flip-flop motion for TDMCS are obtained from the model potential. The images of time-resolving constant-height current mode STM (TCHC STM) calculated from TDMCS results at 200 K exhibit the glimmering near kinks at step edge. The attempt frequency of the transition rates is confirmed as 3.0 THz from the frequecy of the single event of the dimer flip-flop for the period of 56 μs. The calculated results of TDMCS reproduce well results of the experimental TCHC STM.