Tunable metal-semiconductor transition and single-channel transport in armchair carbon nanotubes with two local gates

摘要

We propose a new mechanism to drive metal-semiconductor transitions (MSTs) and single-channel transports (SCTs) in armchair carbon nanotubes by tuning the voltages of two separated local gates. The local gates induce the local self-consistent electrostatic potentials, and then locally shift the band structure of the nanotubes. It is the local shift of the band structure and the difference of the subband quantum number that leads to a MST and a SCT near the Fermi level E_F. We show that the MST has to be achieved by a combined effect of one gate locally shifting the π band below E_F and the other locally shifting the π~* band above E_F. The phenomena discussed here can serve as a foundation for building nanotube electronic circuits and metallic field-effect transistors.