Structural transformation of As-stabilized surfaces caused by Ga-deposition detected by time-resolved surface photo-absorption

Evolution of surface structures during conversion from various As-stabilized surfaces to Ga-stabilized ones is observed by surface photo-absorption. Desorption of As dimers parallel to 110] is observed during the structural change of c(4×4) and (2×4)γ. The evolution of Ga- and As-related peaks is isolated in surface dielectric anisotropy spectra, which are determined using p- and s-polarized surface photo-absorption spectra during the conversion of (2×4)β to a Ga-stabilized (4×2) surface.