Doping- and size-dependent suppression of tunneling in carbon nanotubes

TL;DR

This paper investigates how doping and size influence tunneling suppression in carbon nanotubes, revealing a scaling behavior and predicting reduced suppression with increased doping, along with a crossover in large-radius nanotubes.

Contribution

It introduces a scaling approach to understand doping and size effects on tunneling suppression in carbon nanotubes, predicting new behaviors in multi-walled nanotubes.

Findings

Doping reduces the tunneling suppression exponent $oldsymbol{eta }$.

Scaling approach unifies different critical exponents $oldsymbol{oldsymbol{ extit{ extalpha }}}$ measurements.

Large-radius nanotubes exhibit a crossover from quasiparticle to 1D conductor behavior.

Abstract

We study the effect of doping in the suppression of tunneling observed in multi-walled nanotubes, incorporating as well the influence of the finite dimensions of the system. A scaling approach allows us to encompass the different values of the critical exponent $\alpha $ measured for the tunneling density of states in carbon nanotubes. We predict that further reduction of $\alpha $ should be observed in multi-walled nanotubes with a sizeable amount of doping. In the case of nanotubes with a very large radius, we find a pronounced crossover between a high-energy regime with persistent quasiparticles and a low-energy regime with the properties of a one-dimensional conductor.