Extremely long electron and nuclear spin coherence times have been demonstrated in isotopically pure Si-28 [1,2] making silicon a promising semiconductor material for spin-based quantum information. The two-level spin state of single electrons bound to shallow phosphorus donors in silicon in particular provide well defined, reproducible qubits . An important challenge in these systems is the realisation of an architecture, where we can position donors within a crystalline environment with approx. 20-50nm separation, individually address each donor, manipulate the electron spins using ESR techniques and read-out their spin states.
We have developed a unique fabrication strategy for a scalable quantum computer in silicon using scanning tunneling microscope lithography to precisely position individual P donors in Si  aligned with nanoscale precision to local control gates  necessary to initialize, manipulate, and read-out the spin states [6-8]. We have published our approach to scale-up using 3D architectures for implementation of the surface code .
During this talk I will focus on demonstrating fast, high fidelity single-shot spin read-out , ESR control of precisely-positioned P donors in Si  and our results to demonstrating a two-qubit gate in donor qubits in silicon [12,13]. With important advances in control at the atomic-scale, I will attempt to highlight the benefits of single atom qubits in silicon.
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