Electron-spin-resonance transistors for quantum computing in silicon-germanium heterostructures

We apply the full power of modern electronic band structure engineering and\nepitaxial heterostructures to design a transistor that can sense and control a\nsingle donor electron spin. Spin resonance transistors may form the\ntechnological basis for quantum information processing. One and two qubit\noperations are performed by applying a gate bias. The bias electric field pulls\nthe electron wave function away from the dopant ion into layers of different\nalloy composition. Owing to the variation of the g-factor (Si:g=1.995,\nGe:g=1.563), this displacement changes the spin Zeeman energy, allowing\nsingle-qubit operations. By displacing the electron even further, the overlap\nwith neighboring qubits is affected, which allows two-qubit operations. Certain\nSilicon-Germanium alloys allow a qubit spacing as large as 200 nm, which is\nwell within the capabilities of current lithographic techniques. We discuss\nmanufacturing limitations and issues regarding scaling up to a large size\ncomputer.\n