Electron localization in superlattice-carbon nanotubes

Electronic transport properties of superlattice-carbon nanotubes (SCNTs) attached to semi-infinite clean metallic carbon nanotube (CNT) leads are investigated in the framework of a simple model based on mode (momentum)-space within the tight-binding approximation. This model reduces the numerical calculation time and enables us to use the transfer matrix method to investigate transport in an SCNT. We calculate the localization length and density of states (DOS) for various strengths of boron defect. Our numerical results indicate that the localization length decreases with increasing boron concentration, showing the tendency of the system towards the insulating behavior. Also, we observe a nearly stepwise dependence of the localization length on energy at small boron concentration. By controlling the layered boron concentration, the system can be tuned to yield either localized or extended states. These calculations can be generalized to the magnetic defects embedded in the device, which can act as a spin-filter. Our results can serve as a base for developments in designing nano-electronic devices.