Adsorption of Cs on an InP(110) surface is studied as a function of the Cs coverage using the self-consistent linearized augmented-plane-wave method and a jellium-slab model. Behavior similar to that of the Cs/GaAs(110) system is found, namely, that the phosphorus-derived dangling-bond state near the valence-band maximum plays an important role in the interaction, and, as a result of reduced screening in semiconductors, the chemisorption bond for Cs/InP(110) has a strong prominent ionic character and is situated in a region of the III-V compound substrates much deeper than that of the metal substrates. Quantitative differences between Cs/InP(110) and Cs/GaAs(110) systems are explained by the differences in the energy of their valence levels and the density of surface atoms. Nonmetallic behavior is also expected to occur over almost the whole submonolayer regime. We find that the present calculation of surface band structure for the clean InP(110) surface is in fairly good agreement with the recently obtained experimental dispersions.

• Received 14 August 1992

DOI:https://doi.org/10.1103/PhysRevB.47.9791