In the design of quantum computer architectures that take advantage of the long coherence times of dopant nuclear and electron spins in the solid-state, single-spin detection for readout remains a crucial unsolved problem. Schemes based on adiabatically induced spin-dependent electron tunnelling between individual donor atoms, detected using a single electron transistor (SET) as an ultra-sensitive electrometer, are thought to be problematic because of the low ionisaton energy of the final D- state. In this paper we analyse the adiabatic scheme in detail. We find that despite significant stabilization due to the presence of the D+, the field strengths required for the transition lead to a shortened dwell-time placing severe constraints on the SET measurement time. We therefore investigate a new method based on resonant electron transfer, which operates with much reduced field strengths. Various issues in the implementation of this method are also discussed.
@article{arxiv.quant-ph/0402077,
title = {Single-spin readout for buried dopant semiconductor qubits},
author = {L. C. L. Hollenberg and C. J. Wellard and C. I. Pakes and A. G. Fowler},
journal= {arXiv preprint arXiv:quant-ph/0402077},
year = {2010}
}