Controllable valley splitting in silicon quantum devices
| Autor: | D.W. van der Weide, Charles Tahan, Levente Klein, Susan Coppersmith, Srijit Goswami, Robert Joynt, Patricia M. Mooney, J. O. Chu, Mark Friesen, J. L. Truitt, K. A. Slinker, Mark A. Eriksson, L. M. McGuire |
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| Rok vydání: | 2006 |
| Předmět: |
Physics
Condensed Matter - Materials Science Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics Quantum point contact Energy level splitting Quantum sensor Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences General Physics and Astronomy Spin engineering 02 engineering and technology Zero field splitting Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 01 natural sciences Quantum technology Qubit Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences 010306 general physics 0210 nano-technology Quantum computer |
| Zdroj: | Nature Physics. 3:41-45 |
| ISSN: | 1745-2481 1745-2473 |
| DOI: | 10.1038/nphys475 |
| Popis: | 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 these valleys are split by a large energy does one 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 electronic 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. Comment: Published version, including supplementary materials |
| Databáze: | OpenAIRE |
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