Influence of Atomic Sphere Radii on the Electron-Positron Momentum Density Calculated for SiC within the LMTO-ASA

The atomic sphere approximation consists in replacing the Wigner-Seitz polyhedron, containing individual atom, by the sphere of the same volume. In the case of several not equivalent atoms per primitive cell, e.g. for SiC, the radii of atomic spheres, centred at different atoms, are not uniquely determined and should be judiciously chosen. In the present work one studies the effect of choice of atomic sphere radii on the resulting electron band structure and momentum density as well as the electron-positron momentum density. Calculations were performed for SiC within the linear muffin-tin orbital atomic sphere approximation method.