Imposing changes of band and spin–orbit gaps in GaNBi

We present first-principles pseudopotential plane-wave calculations to explore the effects of alloying of non conventional III–V compound GaN with bismuth. We found a highly nonlinear reduction of the energy gap of GaN for small Bi composition. Consequently the optical band gap bowing is found extremely important and composition dependent. The stronger contribution is due principally to structural and, to less extent, to charge transfer effects. Moreover, because of strong relativistic effects caused by bismuth, we found a giant bowing for the spin–orbit splitting energy of valence band, by far the largest of any III–V ternary alloys.