Dielectric response of As-stabilized GaAs surfaces observed by surface photo-absorption

Abstract
This letter discusses changes in the isotropic and anisotropic surface dielectric response caused by surface conversion from c(4×4) to (2×4) of a GaAs(001) As-stabilized surface, observed using surface photo-absorption. The anisotropic part quantitatively reproduces the change in the surface dielectric anisotropy spectra observed in reflectance difference measurements during this surface conversion. The isotropic part can be measured only by surface photo-absorption and comparison is made with a calculation using a three-phase model consisting of vacuum/As/GaAs.