Microscopic Screening and Phonon Dispersion of Silicon: Moment Expansion for the Polarizability

P. E. Van Camp; V. E. Van Doren; J. T. Devreese

doi:10.1103/PhysRevLett.42.1224

Microscopic Screening and Phonon Dispersion of Silicon: Moment Expansion for the Polarizability

P. E. Van Camp, V. E. Van Doren, and J. T. Devreese

Phys. Rev. Lett. 42, 1224 – Published 30 April 1979

Abstract

A phonon dispersion curve of Si is calculated using the microscopic theory of dielectric screening. The electron energies and wave functions are calculated from a crystal pseudopotential which is self-consistent with the electron-ion pseudopotential. For the polarizability matrix a continued fraction expansion including the zeroth and first moment is used. The first moment is treated as a constant. The results are sensitive to both the self-consistency condition and the closure approximation.