AB-INITIO MOLECULAR-DYNAMICS STUDY OF ADSORPTION AND RESTORATION - SI(100)SE

The adsorption of selenium on the Si(100)2 x 1 surface at the coverage of 0.25, 0.50 and 1.0 ML is studied by the ab initio molecular dynami cs method. It indicates that Si(100):2 x 1 will transfer to the buckle d 2 x 2 reconstruction at 0.25 and 0.50 ML, and finally be restored to 1 x 1 symmetry structure spontaneously induced by the adsorption of S e. The dynamics process of restoration is also simulated, where vibrat ions of Se atoms with a period of about 0.60 ps are found, and the ato ms in dimers vibrate relatively with the same period before the system is annealed. The geometry of the restored 1 x 1 structure at coverage of 1.0 ML is in good agreement with previous studies.