Theory of Cs adsorption on InAs(110)

We present a first-principle study of the stable phase of the Cs-covered In As(1 1 0) surface, in the high coverage regime. The results of our calculat ions reveal the formation of a novel reconstruction, compatible with one-di mensional [1 1 0) Cs wires formed by adatoms at two inequivalent surface si tes. The calculated electronic properties allow a microscopic understanding of the adsorption mechanism and of the wire structure. Adsorption occurs t hrough the outward displacement of alternate surface In cations, involving complete filling of the surface state associated to their dangling bonds. T he As anions participate in the global in-plane charge redistribution. The calculated structural and electronic properties compare well to recent expe rimental low energy electron diffraction and scanning tunneling microscopy data. The results are discussed in comparison with a variety of other alkal i/semiconductor systems: while the adsorption mechanism is the same, the me tal-to-substrate strain is responsible for the structural details of the ad atom chain. (C) 2001 Elsevier Science B.V. All rights reserved,