The oxidation of the GaAs (110) surface

It is demonstrated that, contrary to previous proposals, Ga surface atoms are already involved in the oxidation process for the lowest observable oxygen coverages (0.01 monolayer). A similar involvement of As atoms could not be readily ascertained experimentally, although it is to be expected from energetic considerations. An oxidation model consisting of multiple bridge bonds to both Ga and As surface atoms is proposed, which is consistent with diverse experimental data for the GaAs(110) surface.