Shot Noise Detection on a Carbon Nanotube Quantum Dot

TL;DR

This paper presents an on-chip method to detect high-frequency shot noise in a carbon nanotube quantum dot, revealing super-Poissonian noise during inelastic cotunneling, with detailed measurements across Coulomb diamonds.

Contribution

It introduces a novel on-chip detection scheme using photon assisted tunneling in superconductor junctions for quantum dot noise measurement.

Findings

Shot noise measured over full Coulomb diamonds.

Super-Poissonian noise observed during inelastic cotunneling.

Excited states and inelastic cotunneling clearly resolved.

Abstract

An on-chip detection scheme for high frequency signals is used to detect noise generated by a quantum dot formed in a single wall carbon nanotube. The noise detection is based on photon assisted tunneling in a superconductor-insulator-superconductor junction. Measurements of shot noise over a full Coulomb diamond are reported with excited states and inelastic cotunneling clearly resolved. Super-Poissonian noise is detected in the case of inelastic cotunneling.