First-principles calculations are performed to compute the e<Subscript>33</Subscript> piezoelectric coefficients of GaN, ScN and (Sc<Subscript>x</Subscript>Ga<Subscript>1-x</Subscript>N) alloys exhibiting an alternation of hexagonal GaN, with hexagonal ScN along the c-axis. For Sc compositions larger than 50%, each atom has nearly five nearest neighbors (i.e.,...</subscript></subscript></subscript>

The electronic structures (especially 4f states) of hexagonal and tetragonal erbium silicides are investigated within density functional theory. Contrary to previous theoretical studies on these compounds, Er 4f electrons are treated as valence state electrons, explicitly taking into account the...