Ab initio study of structure and dynamics of the Si(100) surface.

Abstract

We present a full application of the finite-temperature ab initio molecular dynamics to the Si(100) surface. A clear dynamical picture of the system has been obtained: coexistence of different reconstructions, their temperature stability, surface vibrations and phase transitions. The c(4\ifmmode\times\else\texttimes\fi{}2) structure, with its alternate buckled surface dimers, explains the basic Si(100) properties, but it does not completely account for the fine details of the experimental results. The room temperature Si(100) structure corresponds to a mixture of the c(4\ifmmode\times\else\texttimes\fi{}2) and p(2\ifmmode\times\else\texttimes\fi{}2) geometries together with instantaneous symmetriclike twisted dimers configurations.