In-rich (4 × 2) and (2 × 4) reconstructions of the InAs(0 0 1) surface

Based on a first-principles pseudopotential calculation, within the local density approximation, we have studied a series of different structural models for the In-rich InAs(0 0 1) surface, including a very recent model proposed by Kumpf et al. based in X-ray diffraction experiments. Our data suggests that the ζ(4 × 2) model corresponds to the most probable structure, from the energetic point of view. The stability of the ζ(4 × 2) structure is mainly attributed to electrostatic and structural characteristics of the surface. The atomic and electronic structure of this system is analysed in detail. Experimental scanning tunnelling microscopy images are reinterpreted in the lights of our theoretical simulated images for the proposed structure, with a view to explain contradicting experimental and theoretical results.