GaAs equilibrium crystal shape from first principles

[摘要] Surface energies for different GaAs surface orientations have been calculated as a function of the chemical potential. We use an energy density formalism within the first-principles pseudopotential density-functional approach. The equilibrium crystal shape has been derived from the surface energies for the (110), (100), (111), and ((111) over bar) orientations. Under As-rich conditions all four considered surface orientations exist in thermodynamic equilibrium, in agreement with experimental observations. Moreover, our calculations allow us to decide on previous contradictory theoretical values for the surface energies of the (111) and ((111) over bar) facets.

[关键词] SCANNING-TUNNELING-MICROSCOPY;POLAR SEMICONDUCTOR SURFACES;MOLECULAR-BEAM EPITAXY;2X2 RECONSTRUCTIONS;ELECTRONIC-STRUCTURE;GAAS(110) SURFACE;ATOMIC-STRUCTURE;ABINITIO THEORY;ENERGY DENSITY;GROUND-STATE