Electronic charge densities in PbSe and PbTe

The electronic charge densities for PbSe and PbTe are derived from recent pseudopotential-band-structure calculations. The results are displayed as contour plots for individual bands and for the total valence charge. Fractional amounts of charge inside touching spheres around each atom are calculated for different $l$ values by an angular momentum projection method. Rough estimates of the charge transfers in PbSe and PbTe are made. The charge densities for the states forming the gap at the point $L$ of the Brillouin zone are presented and related to pressure and temperature coefficients of the fundamental gap.