Effect of relative rotation of walls on the conductance of double-walled carbon nanotubes

In this paper, we have simulated and investigated the electrical conductance and performance of telescoping double-walled carbon nanotubes (TDWCNTs) when there is a relative rotation between the two walls. Tight-binding (TB) model combined with nonequilibrium Green´s function (NEGF) approach is employed to calculate the electrical conductance of the TDWCNTs. Our results show that there is no or low variation of conductance for some rotation angles while some other rotation angles can give rise to significant and high variation of conductance up to 40-50 percent. One much more important result is that, although the electrical conductance change with relative rotation of the walls, the on/off ratio of the conductance is nearly constant and varies slightly. As a result, TDWCNTs can be suitable for switching applications in nanoelectromechanical system (NEMS) in spite of free rotation between the inner and outer nanotubes.