Proximity and anomalous field-effect characteristics in double-wall carbon nanotubes

TL;DR

This paper investigates how the proximity effect influences the field-effect characteristics in double-wall carbon nanotubes, revealing that metallic phases can induce anomalous behaviors in semiconducting shells.

Contribution

It demonstrates that the anomalous field-effect characteristics in S-M double-wall carbon nanotubes are explained by the proximity effect using a two-band tight-binding model.

Findings

Proximity effect causes semiconducting shells to behave metallically.

Anomalous FEC in S-M DWCNTs is explained by proximity-induced metallic phases.

Theoretical model successfully reproduces observed FEC behaviors.

Abstract

Proximity effect on field-effect characteristic (FEC) in double-wall carbon nanotubes (DWCNTs) is investigated. In a semiconductor-metal (S-M) DWCNT, the penetration of electron wavefunctions in the metallic shell to the semiconducting shell turns the original semiconducting tube into a metal with a non-zero local density of states at the Fermi level. By using a two-band tight-binding model on a ladder of two legs, it is demonstrated that anomalous FEC observed in so-called S-M type DWCNTs can be fully understood by the proximity effect of metallic phases.