dc Josephson Effect in Metallic Single-Walled Carbon Nanotubes

TL;DR

This paper explores how electron-electron interactions in metallic single-walled carbon nanotubes influence the dc Josephson effect, revealing oscillations in supercurrent that enable tunable -junctions, highlighting Luttinger liquid physics.

Contribution

It demonstrates the impact of strong electronic correlations on supercurrent behavior in nanotubes, showing oscillations and the possibility of reversing supercurrent sign, a novel insight into nanotube-based Josephson junctions.

Findings

Oscillations in critical current due to electron interactions.

Signature of Luttinger liquid physics in supercurrent behavior.

Potential to create tunable -junctions.

Abstract

The dc Josephson effect is investigated in a single-walled metallic carbon nanotube connected to two superconducting leads. In particular, by using the Luttinger liquid theory, we analyze the effects of the electron-electron interaction on the supercurrent. We find that in the long junction limit the strong electronic correlations of the nanotube, together with its peculiar band structure, induce oscillations in the critical current as a function of the junction length and/or the nanotube electron filling. These oscillations represent a signature of the Luttinger liquid physics of the nanotube, for they are absent if the interaction is vanishing. We show that this effect can be exploited to reverse the sign of the supercurrent, realizing a tunable \pi-junction.