Predicting the structural, electronic and mechanical properties of three-dimensional boron nitride foam containing sp, sp2 and sp3 hybridized bonds

Abstract

A first-principles approach is utilized to systematically investigate the structural, electronic and mechanical properties from a new BN phase (denoted super-(BN)16). Super-(BN)16 contains sp, sp2 and sp3 hybridized bonds. It is mechanically stable, even though it is energetically unfavorable than c-BN, w-BN, yne-BN, and so on. Due to the different hybridization type and the B-N covalent bonds with ionic characteristics, super-(BN)16 has unequal bonds and bond angles in these equal space positions. The calculated electronic structure showed it is a semiconductor with a direct band gap of 1.94 eV. The electronic states in the region near Fermi level mainly come from the 2p orbitals of the sp hybridized B and N atoms. The elastic constants and moduli of this phase exhibit clear anisotropy and super-(BN)16 should have a low hardness and high ductility. Additionally, it can be obtained from nanosheets, nanotubes and nanoribbons of yne-BN family under pressure.