NUCLEATION OF THE PT(111) RECONSTRUCTION - A SIMULATION STUDY

Recent STM studies [Phys. Rev. Lett. 70 (1993) 1489] have shown an induced reconstruction of the Pt(111) surface when it is exposed to Pt atoms. Using computer simulations we have studied the nucleation of this reconstruction. Additional Pt atoms are incorporated into the surface layer where they form partial dislocations. In-layer islands are shaped by partial dislocations arranged in different patterns. In the smallest islands the partial dislocations form a hexagon. As more atoms are incorporated the islands grow ''legs'' of partial dislocations pointing in the [1BAR1BAR2] directions, as seen in the experiments. The energetics behind the growth pattern is analysed. The barrier for diffusion of adatoms is increased by 0.1 eV across a partial dislocation.