Chiral tubules of hexagonalBC2N

We propose a family of nanotubules originating from a hexagonal ${\mathrm{BC}}_2$N sheet. Because of the anisotropic structure of the ${\mathrm{BC}}_2$N sheet, there are a variety of ways to obtain chiral structures by rolling the ${\mathrm{BC}}_2$N sheets into tubules. We performed first-principles and tight-binding band-structure calculations and predict that the chiral ${\mathrm{BC}}_2$N tubules will behave as semiconductors that can be doped with either acceptors or donors. Since the ${\mathrm{BC}}_2$N sheets have anisotropic conductivity in the in-plane directions, helical currents are expected for the chiral tubules. The tubules will resemble nanoscale coils.