Polaronic effects on the intra-donor 1s→2p± transition energies in GaN structures

Abstract

We report a calculation of the electron–phonon interaction effects on the 1s→2p± transition energies of a donor impurity present in a GaN-bulk in the presence of an external magnetic field. The energy levels are calculated through a variational method by choosing a two parameters gaussian trial wave function. The electron–LO phonon interaction is included by the Improved Wigner–Brillouin Perturbation Theory (IWBPT) as modified by Cohn, Larsen and Lax. Effects of non-parabolicity of the conduction band are also considered. In order to correctly describe the experimental data obtained by Moore et al. for GaN structures, the electron effective mass was used as a fitting parameter, and good agreement between the results was found for electron effective mass mb=0.23me. A resonant split of the 1s→2p+ transition energy is predicted to occur for magnetic field around 140T.