P-richGaP(001)(2×1)/(2×2)surface: A hydrogen-adsorbate structure determined from first-principles calculations

Abstract

We perform first-principles total-energy and electronic structure calculations in order to determine the atomic structure of the P-rich $(2\ifmmode\times\else\texttimes\fi{}1)/(2\ifmmode\times\else\texttimes\fi{}2)$ reconstruction commonly observed for GaP(001) surfaces grown by gas-phase epitaxy. A monolayer of buckled phosphorus dimers stabilized by hydrogen adsorbed in an alternating sequence is found to be energetically stable and to be consistent with the experimental data.