Dimers and divacancy effects on a reconstructed Si(001) surface

Abstract

We have employed a tight-binding molecular-dynamics scheme to study the structural and dynamical behavior of dimers and the divacancy on a Si(001) surface at room temperature. At T=0 K, we conclude that dimers are intrinsically asymmetric but they fluctuate to give on a time average a symmetric appearance at room temperature. However, the presence of a divacancy defect is found to induce and stabilize the formation of buckled dimers in its vicinity. These dimers, in addition, are found to be twisted although, in the defect-free surface, none appears so. A detailed analysis of the structural and dynamical properties of the defect and its influence on the behavior of neighboring dimers is presented and discussed. © 1993 The American Physical Society.