Electronic Structure of Magnesium Silicide and Magnesium Germanide

Abstract

Pseudopotentials previously calculated for metallic magnesium and semiconductors silicon and germanium are used to calculate the electronic energy-band spectra of magnesium silicide and magnesium germanide. Results are obtained for the energy gap and the positions of the valence-band maximum and conduction-band minimum which are in agreement with what is known experimentally about these substances. The use of the energy levels determined is discussed in interpreting ultraviolet reflectance spectra of these compounds. Finally, on the basis of the present calculations, some speculations are made about the nature of the electron and hole energy surfaces in the semimetallic region of the alloy system ${\mathrm{Mg}}_{2}{(\mathrm{Sn})}_{x}{(\mathrm{Pb})}_{1\ensuremath{-}x}$.