Density-functional calculations for self-assembled Bi-nanolines on the InAs(100) surface

Abstract

We have performed an ab initio investigation of the stability, atomic geometry, and electronic properties of the self-assembled bismuth (Bi)-nanolines on the Bi-stabilized indium arsenide (InAs)(100) surface. Our calculations were performed within the local density approximation of the density functional theory, using pseudopotentials to describe the electron-ion interactions. We have examined several metastable Bi nanolines arrangements on the top of the Bi-stabilized InAs(100) surface. Our total energy calculations suggest that the most stable configuration of the Bi nanolines is formed by Bi dimers parallel to the Bi dimers on the Bi/InAs(100) surface. We have found that the structure is metallic with several occupied and unoccupied surface states within the bulk InAs gap region. These states are mainly due to the top and first sublayer Bi atoms. Our theoretically simulated scanning tunneling microscope (STM) image shows a very bright line along the [01¯1] direction, which is consistent with the experimental STM images.