First-principles studies of the electronic and magnetic structures and bonding properties of boron subnitride BN
arXiv:2008.09080 · doi:10.1016/j.jssc.2020.121840
Abstract
Rhombohedral B unit is viewed as a host matrix embedding linear tri-atomic arrangements of elements (E) resulting in a relatively large family of boron-rich compounds with B{E-E-E} generic formulation. The present work focuses on boron subnitride, BN that we express in present context as B{N-B-N}. Within well established quantum density functional theory (DFT) a full study of its electronic properties is provided. Also linear triatomic arrangements in view of the existence in simple compounds such as sodium azide NaN, i.e., Na{N-N-N} and calcium cyanamide, Ca{N-C-N}, we devised Sc{N-B-N} to establish comparison with B{N-B-N}. ScBN is calculated to be cohesive and possessing N-B-N isolated from ScIII with dB-N = 1.33 Å. In B{N-B-N} an elongated dB-N=1.43 Å is identified due to the bonding of N with one of the two B12 boron substructures, B1 with the formation of "3B...N-B-N...3B"-like complex accompanied by a magnetic instability. Spin polarized (SP) calculations led to the onset of magnetization on central boron with M=1 in a stable half-ferromagnetic ground state observed from the electronic density of states (DOS). The results are backed with total energy and calculations in both non-spin-polarized (NSP) and spin-polarized stabilizing the latter configuration over a broad range of volumes from M(V) plots. Further illustrative results are given with the charge densities (total and magnetic) and electron localization function (ELF).