Defects for quantum information processing in silicon

In this chapter, we discuss defects in silicon, primarily focusing on phosphorus donors, from the viewpoint of quantum information processing. We start with a historical perspective on our understanding of the limits to information processing. In doing so, we illuminate why we are so excited about the recent experimental challenges to realize silicon-based quantum computers. After reviewing the spin physics of donors in silicon, we discuss the coherence properties of donor electron and nuclear spins, and evaluate their feasibilities as carriers of quantum information, quantum bits. Recent developments in coherent control of single donor spins in silicon nanoelectronic devices are then outlined.