Quasiparticle effective-mass theory in semiconductors

A scheme for calculating quasiparticle effective masses beyond the standard local-density approximation is presented. Correlation effects beyond the local-density approximation are included in the form of self-energy correction which leads to two important correction factors. The first factor arises from the energy dependence of the self-energy resulting in renormalization of the quasiparticle and the second factor originates from the wave-vector dependence of the self-energy. We demonstrate the feasibility of our approach by calculating the effective masses of some wide-gap semiconductors AlN, GaN, ZnO, and artificial AlGaN2, well known for their technological importance. The obtained quasiparticle effective masses are in excellent agreement with available experimental data.