On the pentaheptite nanotubes

Abstract

Stone-Wales defect in graphene is a bond rotation transforming four adjacent hexagons into the pentaheptite ornament with two pentagons and two heptagons. There are two types of pentaheptite lattices, i.e., hexagonal and rectangular. Each of them can be rolled up to get pentaheptite nanotubes, analogously to the conventional carbon nanotubes obtained by rolling of the graphene. Using full symmetry of these nanotubes, stable configuration is found by numerical density functional theory-based relaxation with initial purely folded configurations. Pentaheptite tubes are less stable than the conventional ones; however, the transition can be induced by an external mechanical stress. New tubes have different electrical properties, most of them being conducting with considerable Fermi level density of states. These properties are exploited to propose electromechanical nanoswitch.