Band Structure of Beryllium by the Augmented-Plane-Wave Method

Abstract

The results of an augmented-plane-wave (APW) calculation of hexagonal-close-packed beryllium are presented in the form of the Fermi energy, energy bands which were extended to energies much higher than the Fermi energy, density-of-states curve below the Fermi energy, and electronic specific heat. The crystalline potential used in calculating the energy bands was obtained by superposing self-consistent Hartree-Fock atomic-beryllium potentials on first-, second-, and third-nearest neighbors, and exchange was treated in the Slater free-electron-exchange approximation. The good agreement between the theoretically and experimentally determined Fermi surfaces which was found previously by the author is discussed. The general features of the density-of-states curve for energies below the Fermi energy are in good agreement with the soft-x-ray emission data, and the electronic specific heat coefficient is in reasonable agreement with published experimental results. The energy bands of hcp beryllium and hcp magnesium are discussed by comparing the logarithmic derivatives of their respective wave functions across the respective APW sphere radii. The results of comparing the logarithmic derivatives of beryllium and magnesium are used to emphasize the close connection between orthogonalized-plane-wave and APW methods.