Equation of state and properties of lithium

Abstract

The equation of state and one-electron properties of fcc and bcc Li are calculated for cell volumes between 0.175 and 3.0 times the experimental zero-pressure volume with use of the linear-combination-of-Gaussian-type-orbitals technique. These calculations utilize two distinct local-density-approximation (LDA) models. The fcc structure is found to be more stable for all volumes considered and for both LDA models, contrary to a recent prediction of bcc stability at high pressures. The bulk properties exhibit LDA-model dependencies similar to those recently noted in Fe, i.e., the best accord with experiment is achieved with the simple Kohn-Sham-Gaspar model. This somewhat surprising outcome holds not only at equilibrium but for pressures up to 250 kbar. The high-pressure band structure of Li is also presented for the first time. That band structure exhibits rather interesting modifications compared to the zero-pressure band structure.