Theoretical Investigations for Surface Reconstructions of Submonolayer InAs Grown on GaAs(001)

Abstract

Surface reconstructions of submonolayer InAs grown on GaAs(001) are investigated using ab initio pseudopotential calculations. Decreasing As chemical potential, calculated formation energies as a function of As chemical potential reveals that the surface reconstructions change from (4 × 3) with one In-As and two As dimers at InAs coverage θ = 0.71 monolayer (ML) to (2 × 4) at θ = 1.38 ML via c(4 × 4) with two In-As and one As dimers at θ = 0.88 ML. It should be noted that the (4 × 3) with two In-As and one As dimers is less stable than the c(4 × 4) with the same dimer constituents. The c(4 × 4) with two In-As and one As dimers is still stable even due to the lattice constraint of GaAs that tend to destabilize c(4 × 4) and (2 × 4) but stabilize many (4 × 3) phases. Consequently, the newly found c(4 × 4) is an intermediate phase to form the (2 × 4) domain on the (4 × 3) surface in InAs/GaAs(001).