First-principles study of vibrational spectra on dihydride-terminated Si(001)/H surfaces

摘要

The vibrational spectra on the dihydride-terminated Si(001) surfaces are calculated with a density-functional theory in combination with the finite-element method. On the 1 x 1 surface, the stretching modes of the Si--H bonds are found to split as a result of the H--H interaction between adjacent dihydride units. The width of this splitting is estimated to be about 50 cm(-1). Especially the upper peak corresponds to the stretching mode of the lying Si--H bond of the canted dihydride unit. Its frequency is expected to be similar to that of the trihydride unit on the atomically rough Si(001)/H surface. (C) 2000 Elsevier Science B.V. All rights reserved. References: 22