POLARIZATION-DEPENDENT PHOTOEMISSION EXAFS INVESTIGATION OF THE INP(110) SURFACE-STRUCTURE

The atomic geometry of the cleaved InP(110) surface is investigated by polarization-dependent photoemission extended X-ray absorption fine structure (PEXAFS). The P 2p PEXAFS for InP(110) surfaces are acquired at various polarization angles. The data are analyzed by conventional Fourier transform and curve fitting procedures. Theoretical backscattering phase function plus absorber phase function were used for phase analysis. For the clean InP(110) surface, the average (first) P-In bond length is 2.44 +/- 0.04 angstrom, which corresponds to a contraction by approximately 4% in comparison to the bulk P-In interatomic distance of 2.54 angstrom. The second (P-P) nearest neighbor distance is reduced by 0.1 angstrom as compared to its bulk distance of 4.15 angstrom. The third (P-In) distance obtained is close to its bulk value. The results, which are in very good agreement with previous theoretical ab initio total energy pseudopotential calculations and low energy electron diffraction (LEED) studies, support the picture of a relaxed InP(110) surface.