Electronic properties of diamond and silicon

Abstract

Hartree-Fock electron energy bands for Silicon have been obtained, and the energy dependent imaginary part of the dielectric constant has been obtained from the theoretical Hartree-Fock results. These theoretical results are compared with experimental data and other theory. It is found that this is the first self-consistent Silicon band calculation to predict the correct ordering of the lower conduction bands at the center of the zone. The method used consists of obtaining the self-consistent first-order density matrix by means of a modified form of the Adams~Gi1bert local orbitals equation, which solves the Hartree-Fock problem in a rotated space. Special techniques are presented for obtaining the solutions to this equation for the case of covalent materials. Electron-electron correlation is added via a recently modified version of the electronic polaron method which is suitable for wide band narrow gap materials. Theoretical X-ray structure factors are also obtained for Silicon as well as for diamond. These are obtained directly from.the local orbitals and agree very well with experimental results.