The electronic and transport properties of (VBz)n@CNT and (VBz)n@BNNT nanocables

Abstract

The electronic structures and transport properties of prototype carbon nanotube (CNT) (10,10) and boron–nitride nanotube (BNNT) (10,10) nanocables, including (VBz)_n@CNT and (VBz)_n@BNNT (where Bz = C₆H₆), are investigated using the density functional theory (DFT) and the non-equilibrium Green's function (NEGF) methods. It is found that (VBz)_n@CNT shows a metallic character while (VBz)_n@BNNT exhibits a half-metallic feature. Both (VBz)_n@CNT and (VBz)_n@BNNT nanocables show spin-polarized transport properties, namely, spin-down state gives rise to a higher conductivity than the spin-up state. For (VBz)_n@CNT, the CNT sheath contributes the metallic transport channel in both spin-up and spin-down states, while the (VBz)_n core is an effective transport path only in the spin-down state. For (VBz)_n@BNNT, the BNNT sheath is an insulator in both spin-up and spin-down states. Hence, the transport properties of the (VBz)_n@BNNT nanocable are attributed to the spin-down state of the (VBz)_n core. The computed spin filter efficiency of (VBz)_n@CNT is less than 50% within the bias of −1.0 to 1.0 V. In contrast, the spin filter efficiency of (VBz)_n@BNNT can be greater than 90%, suggesting that the (VBz)_n@BNNT nanocable is a very good candidate for a spin filter. Moreover, encapsulating (VBz)_n nanowires into either CNTs or BNNTs can introduce magnetism and the computed Curie or Neél temperatures of both (VBz)_n@CNT and (VBz)_n@BNNT are higher than 2000 K. These novel electronic and transport properties of (VBz)_n@CNT and (VBz)_n@BNNT nanocables render them as potential nanoparts for nanoelectronic applications.