Lattice Dynamics of Beryllium Using a Pseudopotential Approach

The lattice dynamics of Be is discussed within the framework of the local pseudopotential approximation. Calculations are made in the first instance using a basic pseudopotential computed from the orthogonalized-plane-wave band-structure results of Loucks and Cutler. Comparison with experimental phonon dispersion relations shows, however, poor agreement. Calculations are also made using Heine-Animalu model potentials, with similar results. Finally, the experimental data are inverted to obtain an experimental pseudopotential. The latter is used to make a band-structure calculation, and the resulting Fermi surface is compared with that derived from de Hass-van Alphen experiments.