Properties of hexagonal ScN versus wurtzite GaN and InN

Local-density approximation calculations are performed to compare properties of hexagonal ScN with those of wurtzite GaN and InN. A nearly five-times coordinated hexagonal structure is found to be (meta)stable in ScN, unlike the wurtzite structure. Structural, dielectric, and optical properties of this stable hexagonal phase are predicted to be rather different from those of wurtzite GaN and InN. This implies that disordered hexagonal ${\mathrm{Sc}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}\mathrm{N}$ and ${\mathrm{Sc}}_{1\ensuremath{-}x}{\mathrm{In}}_{x}\mathrm{N}$ alloys are very attractive both fundamentally and technologically.