  We analyze the influence of the Mg concentration on several important
properties of the band structure of ZnMgO alloys in wurtzite structure using ab
initio calculations. For this purpose, the band structure for finite
concentrations is defined in terms of the Bloch spectral density, which can be
calculated within the coherent potential approximation. We investigate the
concentration dependence of the band gap and the crystal-field splitting of the
valence bands. The effective electron and hole masses are determined by
extending the effective mass model to finite concentrations. We compare our
results with experimental results and other calculations.
