We present efficient methods to reliably characterize and tune gate-defined semiconductor spin qubits. Our methods are designed to target the tuning procedures of semiconductor double quantum dot in GaAs heterostructures, but can easily be adapted to other quantum-dot-like qubit systems. These tuning procedures include the characterization of the inter-dot tunnel coupling, the tunnel coupling to the surrounding leads and the identification of the various fast initialization points for the operation of the qubit. Since semiconductor-based spin qubits are compatible with standard semiconductor process technology and hence promise good prospects of scalability, the challenge of efficiently tuning the dot's parameters will only grow in the near future, once the multi-qubit stage is reached. With the anticipation of being used as the basis for future automated tuning protocols, all measurements presented here are fast-to-execute and easy-to-analyze characterization methods. They result in quantitative measures of the relevant qubit parameters within a couple of seconds, and require almost no human interference.
@article{arxiv.1801.03755,
title = {Tuning methods for semiconductor spin--qubits},
author = {Tim Botzem and Michael D. Shulman and Sandra Foletti and Shannon P. Harvey and Oliver E. Dial and Patrick Bethke and Pascal Cerfontaine and Robert P. G. McNeil and Diana Mahalu and Vladimir Umansky and Arne Ludwig and Andreas Wieck and Dieter Schuh and Dominique Bougeard and Amir Yacoby and Hendrik Bluhm},
journal= {arXiv preprint arXiv:1801.03755},
year = {2018}
}