Anomalous Conductance Quantization in Carbon Nanotubes

TL;DR

This paper reports on the observation of conductance plateaus in carbon nanotubes that are spaced by the quantum of conductance, exploring their behavior under various experimental conditions and discussing their unusual origin.

Contribution

It presents experimental evidence of anomalous conductance quantization in carbon nanotubes and investigates its dependence on bias, temperature, and magnetic field.

Findings

Conductance plateaus spaced by e^2/h observed in nanotubes.

Quantization appears without typical band or spin degeneracy.

Behavior varies with bias voltage, temperature, and magnetic field.

Abstract

Conductance measurements of carbon nanotubes containing gated local depletion regions exhibit plateaus as a function of gate voltage, spaced by approximately e2/h, the quantum of conductance for a single (non-degenerate) mode. Plateau structure is investigated as a function of bias voltage, temperature, and magnetic field. We speculate on the origin of this surprising quantization, which appears to lack band and spin degeneracy.