Bi-covered InAs(1 1 0) surfaces: An ab initio study

In this work we have performed an ab initio investigation of the Bi-covered InAs(1 1 0) surface. We have considered two different structural models viz. ECLS and (1 × 2) missing row model. Our total energy results indicate that the (1 × 2) model is energetically more favourable than the ECLS model, thus, supporting the recent experimental results by Betti et al. [Phys. Rev. B 59 (1999) 15760]. However, the calculated equilibrium atomic geometry indicates some disagreement with respect to the experimental measurements. The “surface electronic topology” of the Bi/InAs(1 1 0) surface was investigated through simulations of scanning tunneling microscopy (STM) images, where we inferred a semimetallic character along the Bi-chains of the (1 × 2) model.