Detecting Single-Atom Nuclear Spins In Silicon

In work that could aid development of quantum-computing devices with high-density data storage and processing capabilities, researchers have for the first time controlled and detected the nuclear spin of a single dopant atom in a silicon chip. In quantum computing, two quantum states, such as up and down spins, are used to store bits of information called quantum bits, or qubits. Qubits have been based on spins of electrons, ions in high vacuum, large ensembles of nuclei in the solid state, and single nuclei in diamond. Andrea Morello of the University of New South Wales, in Australia, and coworkers have now used magnetic resonance to control and read out the spin of a single phosphorus nucleus on a silicon chip with 99.8% accuracy, the highest qubit accuracy ever achieved in the solid state (Nature, DOI: 10.1038/nature12011). Nuclear qubits can store information longer and more accurately than electron qubits. And silicon is already used in microelectronics, so achieving nuclear spin control and readout in silicon is more practical than in a vacuum or diamond.