Новые соединения нитрида бора с атомами в sp+sp2-гибридизованном состоянии, сформированные на основе слоя BN-L4-8

Abstract

The density functional theory (DFT) method was used to determine the crystal structures and electronic properties of new layered polymorphic varieties of boron nitride with a graphyne-like structure. The structures of new graphyne-like monolayers consist of boron and nitrogen atoms in the sp- and sp2-hybridized state and were model-built from a layer of graphene-like boron nitride BN-L4-8 by partial replacement of atoms in the three-coordinated (sp2-hybridized) state by atoms in the two-coordinated state (sp-hybridized). As a result of theoretical analysis, the possibility of the existence of seven sp + sp2 new structures of boron nitride was established: one α-type, three β-types and three γ-types, differing in the proportion of atoms in the sp-hybridized state and their spatial arrangement. However, two of the three structural varieties with a minimum content of atoms in the sp-hybridized state (γ-type) turned out to be unstable and, in the process of geometric optimization, were transformed into structures of graphene-like layers of boron nitride. The structure of the BN-L4-8-γ2 layer passed into the structure of the original graphene-like layer BN-L4-8, while the structure of the BN-L4-8-γ3 layer passed into the structure of the graphene-like layer BN-L4-6-8, where there are no atoms in the sp-hybridized state. The sublimation energies of the new polymorphic varieties range from 16.23 eV/(BN) to 16.70 eV/(BN). The band gap varies from 3.777 eV to 3.878 eV.