First-principles study of the Cl and Br adsorbed Si(100) surfaces

Abstract

We have studied the atomic and electronic structure of the Cl and Br adsorbed Si(100) surfaces using density-functional theory calculations. We find that the Cl- and Br-terminated Si(100)-(2x1) surfaces show many adsorbate-induced surface electronic features, the energy levels and charge characters of which explain well the electronic origin of the Cl and Br hoppings observed in recent scanning-tunneling-microscopy (STM) experiments. The atomic structures and simulated STM images of Cl and Br vacancies are also examined. The vacancy structures underlying experimental STM images are identified, and the experimental bias-voltage dependence of Cl and Br vacancy images is reproduced in our simulations.