Investigation of the electronic structure of tetragonal B3N3 under pressure

In this paper, we perform self-consistent field relaxation and electronic structure calculations of tetragonal B3N3 based on density functional theory, using LDA pseudopotential in the pressure range between -30 and + 160 GPa. Although metallic B3N3 has a honeycomb structure, according to the electronic band structure, it has bulk properties (not layered) with effective mass non-interacting electron gas behavior near Fermi level (not Dirac massless) and a small anisotropy, about 0.56 in effective mass in the direction of MA relative to XM. Electronic calculations of the B3N3 under pressure show that increasing positive pressure causes the decrease of Fermi energy and total electronic density of states at Fermi level, due to the ionic bonding nature in the B3N3. The Fermi energy increases a little in pressure ranges of about + 100 to + 160 GPa. According to performed projected density of states calculations of the B3N3 under pressure, which p orbitals of boron and nitrogen atoms with three sp(2) hybridized bonding have the most contribution in the electronic states at Fermi level, that have spatial distribution perpendicular to honeycomb planes in pressure range of -30 to + 160 GPa, like p(z) orbitals in graphene. In overall, the contribution of the p orbitals of nitrogen atoms is greater than similar p orbitals of boron atoms. Accordingly, the orbitals of nitrogen and boron atoms with higher order, sp(3) hybridized bonding have negligible electronic contribution at Fermi level in the all pressure range.