Dynamical analysis of low-energy-electron-diffraction intensities from CdTe(110)

An analysis of the structure of the (110) surface of CdTe is performed by comparing dynamical calculations of elastic-low-energy-electron-diffraction (ELEED) intensities with those measured at T=110 K. Prior analyses of ELEED intensities from compound semiconductor surfaces are extended by considering energy-dependent (Hara) models of the exchange potential and by calculating the overlapping atomic charge densities relativistically because both Cd and Te occur in the fifth row of the Periodic Table. A description of the measured intensities is achieved which is comparable to those obtained earlier for analogous surfaces of other compound semiconductors, i.e., GaAs(110), InSb(110), InP(110), GaP(110), and ZnTe(110). The resulting best-fit structures consist of two-layer reconstructions characterized by rotation angles in the range of 1=30.51.5°and relaxation of the rotated top layer toward the substrate by 0.050.05. In the second layer the Cd species is moved upward by 0.09 and the Te downward by this amount, to within an uncertainty of 0.05. This range of structures is essentially identical to the structures found earlier for GaAs(110) and InSb(110), a surprising result because CdTe is considerably more ionic than GaAs and InSb.