A comparative study of Sb bonding on group IV semiconductor substrates
To appear in Phys. Rev. B (1997)
Semiconductor Physics Group, Department of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, United Kingdom
We present the results of ab initio pseudopotential
density functional calculations for the geometry and bonding of the
Si(001)/Sb(2x1) and Ge(001)/Sb(2x1) surfaces. The Sb dimers are found
to be symmetric, with bond lengths of 2.96 A and 2.92 A on the Si and
Ge substrates respectively. We thus concur with recent theoretical
work which concluded that the asymmetric Sb dimer model for the Ge
substrate, favoured by surface x-ray diffraction (SXD) studies, is
incorrect. Furthermore, we calculate that the monolayer-averaged
chemisorption energy of Sb on the Si substrate is 0.48 eV per dimer
greater in magnitude than on the Ge substrate, and discuss the
implications for surfactant mediated growth.
Stephen Jenkins
Last modified: Wed Jul 30 12:36:50 BST 1997