Pauli spin blockade in carbon nanotube double quantum dots

TL;DR

This paper demonstrates Pauli spin blockade in carbon nanotube double quantum dots, showing current suppression and modeling spin states, which suggests potential for single-spin readout in nanotube-based quantum devices.

Contribution

It provides experimental evidence and theoretical analysis of spin blockade in nanotube quantum dots, highlighting their suitability for quantum spin readout applications.

Findings

Current suppression observed under negative bias

Differential conductance matches theoretical spin-blockade model

Potential for single-spin readout in nanotubes

Abstract

We report Pauli spin blockade in an impurity defined carbon nanotube double quantum dot. We observe a pronounced current suppression for negative source-drain bias voltages which is investigated for both symmetric and asymmetric coupling of the quantum dots to the leads. The measured differential conductance agrees well with a theoretical model of a double quantum dot system in the spin-blockade regime which allows us to estimate the occupation probabilities of the relevant singlet and triplet states. This work shows that effective spin-to-charge conversion in nanotube quantum dots is feasible and opens the possibility of single-spin readout in a material that is not limited by hyperfine interaction with nuclear spins.