Positron energy levels in semiconductors

Positron affinities, deformation potentials and lifetimes are calculated in diamond, Si, SiC, and BN bulk cubic semiconductors using the first principles pseudopotential and linear-muffin-tin-orbital (LMTO) methods. Both the electron and positron energies are calculated within the local density approximation (LDA) and generalized gradient approximation (GGA). It is observed that the LMTO calculated values of quantities of interest are systematically lower than those calculated with the pseudopotential method. Results further show that the GGA correction for the electron energy levels is not very important in positron calculations. The calculated positron affinity in SiC is found to be in reasonable agreement with experiment. Positron properties for other materials are also compared with experimental data available.