New BN polymorphs with two-dimensional structure

The calculation of the structure and electronic characteristics of polymorphic varieties of boron nitride with a two-dimensional structure was performed by the methods of the density functional theory. The possibility of stable existence of three main structural varieties is established: BN-L-6, BN-L4-8 and BN-L4-6-12. The sublimation energies of these polymorphs of boron nitride are 18.14, 17.36, and 17.14 eV/(BN), respectively. The BN-L-6 layer has a structure similar to that of experimentally synthesized hexagonal boron nitride. The layers BN-L4-8 and BN-L4-6-12 are new polymorphic varieties of boron nitride. The band gap of these layers is about 3.9 eV. This value is less than the calculated value of 4.69 eV for the band gap of the BN-L-6 layer.