Controllable valley splitting in silicon quantum devices

By S. Goswami, K. Slinker, M. Friesen, L. McGuire, J. L. Truitt, C. Tahan, L. Klein, J. Chu, P. Mooney, D. Weide and 3 more. 2006

208 citations recorded by the source corpus.

Silicon has many attractive properties for quantum computing, and the quantum-dot architecture is appealing because of its controllability and scalability. However, the multiple valleys in the silicon conduction band are potentially a serious source of decoherence for spin-based quantum-dot qubits. Only when a large energy splits these valleys do we obtain well-defined and long-lived spin states appropriate for quantum computing. Here, we show that the small valley splittings observed in previous experiments on Si–SiGe heterostructures result from atomic steps at the quantum-well interface. Lateral confinement in a quantum point contact limits the electron wavefunctions to several steps, and enhances the valley splitting substantially, up to 1.5 meV. The combination of electrostatic and magnetic confinement produces a valley splitting larger than the spin splitting, which is controllable over a wide range. These results improve the outlook for realizing spin qubits with long coherence times in silicon-based devices.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/9a8b5766466d3ec988a5d374eac2982cb4f22593

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In Atomic and Molecular Physics, and Optics

  1. A. Morello
  2. Gerhard Klimeck
  3. Andrew Dzurak

In Electrical and Electronic Engineering

  1. A. Morello
  2. Gerhard Klimeck
  3. Andrew Dzurak

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