Effect of the Surface-Atomic Positions on Reflectance Difference Spectra of [001]-GaAs β2 Structure

Abstract
The role of surface atomic positions in reflectance difference (RD) spectra of the GaAs(001)-(2 ×4)β2 structure is studied using the s p 3 s * tight-binding method. Here we assume that the surface atomic positions are effectively changed by variation of two kinds of transfer energies. It was found that the As-As distance change in surface As dimer causes an energy shift of the RD spectral peak, while the distance change between surface As and substrate Ga affects not the peak position but the peak width. These calculation results are compared with the results of recent experiments.