Nonchiral BN Haeckelite nanotubes

A new class of boron-nitrogen (BN) nanotubes composed of tetragons, pentagons, hexagons, heptagons, and octagons is considered. By analogy with carbon nanotubes of the same topological structure, these nanotubes were called Haeckelites. The geometry, energetics, and electronic properties were studied in detail for two regular mutual arrangements of the polygons. It was found that Haeckelite nanotubes are dielectrics with the energy gap $E_g=3.24{-}4.09\,$eV. As the nanotube diameter increases, the energy gap $E_g$ decreases, approaching the value for the corresponding planar Haeckelite layer. The ground-state energy of the Haeckelite BN nanotubes is 0.3 eV/atom higher than that of well-known hexagonal BN nanotubes.