Square- and hexa-cross sectional carbon and boron-nitride nanoneedles – A theoretical study

Square- and hexa-cross sectional carbon nanoneedles and their boron-nitride counterparts are investigated as a new class of nanomaterials. In contrast with the ordinary carbon nanotubes, the band gaps of the introduced carbon nanoneedles are not strongly dependent on the size of the cross sections, whereas for the boron-nitride needles such a dependency is not observed. Note that any attempts to optimize the octa-cross sectional nanoneedles, change the structure to an ordinary nanotubes; therefore it seems that octa-cross sectional nanoneedles could not be synthesized. Topological analysis also indicates that although CC bonds have covalent nature, the BN bonds show ionic character.