Structure of InSb(001) surface

Abstract

The InSb(001) surface has been studied experimentally, using room temperature scanningtunnelling microscopy (RT STM), and theoretically, using ab initio density functionaltheory (DFT) calculations. RT experimental STM images show bright lines runningalong the bulk crystal [110] direction. Resolved features between the bright lineswhose appearance depends on the applied bias voltage confirm clearly the c(8 × 2) reconstruction of this surface. Our calculations, which arereported for this surface for the first time, include the reconstructed4 × 2 andc(8 × 2) surfaces, the latter according to the so-calledζ-model proposed previously by Lee et al and Kumpf et al. A ‘defective’ structure proposedpreviously by Kumpf et al, which contains an extra In atom within a top bilayer is alsoconsidered. In all cases, we obtained stable structures. Calculated STM images for the c(8 × 2) reconstruction obtained using the Tersoff–Hamann approximation compare extremely wellwith the experimental ones. We also find that the defect structure may not beclearly visible in the STM images. Finally, a brief discussion is given on the other,although closely related, phase of the same surface observed previously in lowtemperature (LT) experimental STM images (Goryl et al 2007 Surf. Sci. 601 3605).