Pseudopotential Models for Pb and Mg: Convergence Properties

Abstract

The convergence properties of Fermi-surface pseudopotential calculations are discussed. It is found for Mg and for Pb that previous models which use only a relatively small number of plane waves are inadequate, particularly when pressure derivatives of Fermi-surface cross sections are calculated. Convergence studies are presented for both materials. It is found for Mg that a local-pseudopotential model if converged can be satisfactory and thus that a nonlocal model is not required. For Pb it is found that several of the discrepancies between experimental results and the model of Anderson et al. can be attributed directly to nonconvergence of their model. A pseudopotential model for the Pb Fermi surface is presented which gives a quite satisfactory description of the de Haas-van Alphen results both at normal volume and under pressure.