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Using first principles total energy calculations within the the full-potential linearized augmented plane wave (FP-LAPW) method, we have investigated the structural and electronic properties of Sc x Ga 1Àx N, with Sc concentrations varying from 0% up to 100%. In particular we have studied the relative stability of several configurations of Sc x Ga 1Àx N in wurtzite-like structures (the ground state configuration of GaN), or in rocksalt-like structures (the ground state configuration of ScN). It is found that for Sc concentrations less than %65%, the favored structure is a wurtzite-like one, while for Sc concentrations greater than %65%, the favored structure is a NaCl-like structure. It is also found that for the wurtzitelike crystals, the fundamental gap is large and direct. For the rocksalt crystals the fundamental gap is small and indirect, but with an additional larger direct gap. In agreement with the experiments of Little and Kordesch [Appl. Phys. Lett. 78, 2891 (2001)] we found a decrease of the band gap with the increase of the Sc concentration.

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