Semiconductor polar surfaces: mechanisms of the stability of non-reconstructed III-V ((1)over-bar(1)over-bar(1)over-bar) surfaces

The mechanisms of the stability of bulk terminated semiconductor polar ((11 1) over bar) surfaces are investigated for the first time with ab initio me thods. In the cases of InAs((111) over bar), InP((111) over bar) and GaP((1 11) over bar), charge is found to be removed from the surfaces, which avoid s an electrostatic catastrophe and stabilizes the surfaces. These new findi ngs properly account for the experimental existence of these unreconstructe d surfaces. The GaAs((111) over bar) surface is, however, predicted to be u nstable in accordance with experiment. (C) 1999 Elsevier Science B.V. All r ights reserved.