Single spins in silicon see the light

Abstract

The spin state of a single erbium atom in a tiny silicon transistor has been probed using laser light. The finding opens a path towards a hybrid spin–photon quantum-computing architecture. See Letter p.91 Central to most proposed schemes for solid-state quantum information technologies is the ability to detect the state of single electron spins. Electrical and optical read-out schemes have been demonstrated, but have yet to attain the high fidelities required for quantum information applications. Chunming Yin et al. have developed a hybrid scheme that promises to overcome these earlier efficiency obstacles. Specifically, they use optical excitation with high resolution to address an individual spin and change its charge state; this change is then detected efficiently with an electrical read-out.