Structural and electronic properties of bismuth and lead nanowires inside carbon nanotubes

Structural and electronic properties of very thin bismuth and lead nanowires encapsulated inside zigzag carbon nanotubes are investigated by density-functional calculations. As is expected, these properties are found to be heavily dependent on the configuration of the nanowire and the diameter of the nanotube, but the inclusion of spin-orbit interaction in the calculation significantly modifies the energy bands of the hybrid system, opens subband spacing, and induces semiconductor-metal transition. These results should be observed by the scanning tunneling spectroscope and could serve as a reference for deriving a variety of configurations of bismuth and lead nanowires by choosing proper carbon nanotubes.