Structural studies of Ga-adsorbed Si(111)√3¯×√3¯ surfaces by low-energy electron diffraction

Abstract
The surface geometry of Si(111)(√3 × √3 )-Ga has been studied by comparing the experimentally obtained curves of intensity versus energy (I-V) from low-energy electron diffraction with calculated curves for several structural models, with variation of the structural parameters for each model. The lowest R factor of 0.25 has been obtained for a substitutional model in which (1/3 of a monolayer of Si atoms in the topmost layer has been replaced by Ga atoms. However, even for this model the agreement between experimental and theoretical spectra is not good enough for a reliable solution of this structural problem.