Electronic structure of magnesium nitride-fluorides from first-principles calculations

Abstract

Electronic structure and stability have been determined from first-principles calculations for the magnesium nitride-fluorides Mg 2NF and Mg 3NF 3, as well as for the binaries MgF 2 and Mg 3N 2. These calculations show that the compounds are ionic to a first approximation. In the nitride-fluorides the valence bands are mainly determined by the N 2p states while the F 2p states are well separated from the N 2p bands and lie 3.5–5.1 eV below the Fermi level. The bottom of the conduction bands is determined by the empty 3s states of the anions. The energy gap decreases steadily with increasing nitrogen content.