Singlet-Triplet Physics and Shell Filling in Carbon Nanotube Double Quantum Dots
Abstract
An artifcial two-atomic molecule, also called a double quantum dot (DQD), is an ideal system for exploring few electron physics. Spin-entanglement between just two electrons can be explored in such systems where singlet and triplet states are accessible. These two spin-states can be regarded as the two states in a quantum two-state system, a so-called singlet-triplet qubit. A very attractive material for realizing spin based qubits is the carbon nanotube (CNT), because it is expected to have a very long spin coherence time. Here we show the existence of a gate-tunable singlet-triplet qubit in a CNT DQD. We show that the CNT DQD has clear shell structures of both four and eight electrons, with the singlet-triplet qubit present in the four-electron shells. We furthermore observe inelastic cotunneling via the singlet and triplet states, which we use to probe the splitting between singlet and triplet, in good agreement with theory.
Cite
@article{arxiv.0711.3245,
title = {Singlet-Triplet Physics and Shell Filling in Carbon Nanotube Double Quantum Dots},
author = {H. Ingerslev Jørgensen and K. Grove-Rasmussen and K. -Y. Wang and A. M. Blackburn and K. Flensberg and P. E. Lindelof and D. A. Williams},
journal= {arXiv preprint arXiv:0711.3245},
year = {2008}
}
Comments
Supplement available at: http://www.fys.ku.dk/~hij/public/singlet-triple_supp.pdf