Reconstruction transition (4 x 2) → (2 x 4) on the (001) surfaces of InAs and GaAs

Phase transitions involving various atomic configurations on the (001) surfaces of GaAs and InAs were studied by RHEED. A kinetic scheme of the interaction between the As4 flow and the surface is proposed and the main equations describing the transitions are modified so as to correspond to the As4 (rather than As2) flux. A model of the (4 x 2) → (2 x 4) transition is suggested for reconstruction of a layer of metal atoms with subsequent stabilization by the adsorption of arsenic atoms. A considerable difference of the surface transitions in GaAs from that in InAs consists in greater force constants (more rigid bonds) in the former case. A significant role in the continuous evolution from (2 x 4)β to (4 x 2) phase in GaAs belongs to metastable disordered phases