Coherent Beam Splitter for Electronic Spin States

• Published in: Science (American Association for the Advancement of Science) Vol. 327; no. 5966; pp. 669 - 672
• Main Authors: Petta, J.R, Lu, H, Gossard, A.C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 05-02-2010; The American Association for the Advancement of Science
• Subjects: Applied sciences; Beam splitting; Electric potential; Electron spin; Electronics; Electrons; Exact sciences and technology; Information technology; Integrated circuits; Integrated circuits by function (including memories and processors); Interferometers; Magnetoelectric, magnetostrictive, magnetoacoustic, magnetooptic and magnetothermal devices. Spintronics; Molecular electronics, nanoelectronics; Oscillators; Quantum dots; Quantum mechanics; Quantum states; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors; Singlet state; Tunnels; Quantum dot; Singlet state; Single electron device; JJ coupling; Electron spin; Implementation; Nanoelectronics; Triplet state; Integrated circuit; Beam splitter; Quantum processor; Quantum oscillation; ns range; Spintronics
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1183628

Rapid coherent control of electron spin states is required for implementation of a spin-based quantum processor. We demonstrated coherent control of electronic spin states in a double quantum dot by sweeping an initially prepared spin-singlet state through a singlet-triplet anticrossing in the energy-level spectrum. The anticrossing serves as a beam splitter for the incoming spin-singlet state. When performed within the spin-dephasing time, consecutive crossings through the beam splitter result in coherent quantum oscillations between the singlet state and a triplet state. The all-electrical method for quantum control relies on electron-nuclear spin coupling and drives single-electron spin rotations on nanosecond time scales.