Effects of defect on Ge(100) surface phase transitions

In this study, critical behaviour of Ge(100) surfaces with %0, %1 and %2 defects is intestigated by using cooling algorithm which is improved from Creutz Cellular Automaton based on Ising Model. The simulation are carried on rectangular lattice with linear dimensions Lx×Ly=30×300, 60×600, 90×900 and 120×1200 using periodic boundry conditions. The investigations showed that to obtain dimer orientations agreement with experimental STM surface images, spin averages must be seperated with ? proportion. Infinite lattice critical temperatures corresponding to defects are obtained and compared with experimental and theoretical results. Finally, we show that surfaces with %2 defects is in good agreement with experimental STM surface image.Key Words : Ge(100) surface, Cellular Automaton, Ising Model, Surface reconstruction, c(4×2)?2×1 phase transition, c(4×2) reconstruction, p(2×2) reconstruction, 2×1 reconstruction, critical behaviour.