Luttinger Liquid Behavior in Carbon Nanotubes

TL;DR

This paper provides experimental evidence that single-walled carbon nanotubes exhibit Luttinger liquid behavior, characterized by power-law conductance dependence on temperature and voltage, aligning with theoretical predictions for 1D interacting electron systems.

Contribution

It demonstrates direct conductance measurements of individual SWNT ropes showing Luttinger liquid behavior consistent with theory.

Findings

Power-law conductance dependence on temperature and voltage observed.

Experimental exponents match theoretical Luttinger liquid predictions.

Supports SWNTs as a platform for studying 1D correlated electron systems.

Abstract

An interacting one-dimensional (1D) electron system is predicted to behave very differently than its higher-dimensional counterparts. Coulomb interactions strongly modify the properties away from those of a Fermi liquid, resulting in a Luttinger liquid (LL) characterized by a power-law vanishing of the density of states at the Fermi level. Experiments on one-dimensional semiconductor wires and fractional quantum Hall conductors have been interpreted using this picture, but questions remain about the connection between theory and experiment. Recently, single-walled carbon nanotubes (SWNTs) have emerged as a new type of 1D conductor that may exhibit LL behavior. Here we present measurements of the conductance of individual ropes of such SWNTs as a function of temperature and voltage. Power law behavior as a function of temperature or bias voltage is observed: G~ T^a and dI/dV ~ V^a. Both the power-law functional forms and the inferred exponents are in good agreement with theoretical predictions for tunneling into a LL.