Electronic structures ofB1MoN, fccMo2N, and hexagonal MoN

The electronic structures of B1 MoN, fcc ${\mathrm{Mo}}_2$N, and hexagonal MoN were observed by photoelectron spectroscopic measurement. The B1-MoN phase has been predicted to be a high-$T_c$ superconductor because of a large density of states at Fermi level. The observed electronic structure of the stoichiometric B1-MoN phase is different from that of the real B1-MoN type. The nitrogen excess B1-${\mathrm{MoN}}_{\mathrm{x}}$ (x≥1.3) phase, however, shows the B1-type electronic structure. This is explained by the occurrence of a nitrogen vacancy in the apparent stoichiometric B1 phase and the occupation of the nitrogen vacancy in the nitrogen-excess B1 phase. This property is related to the previously reported low $T_c$ of the B1-MoN crystals.