Charge and spin manipulation in a few-electron double dot

J. R. Petta, A. C. Johnson, J. M. Taylor, A. Yacoby, M. D. Lukin, C. M. Marcus, M. P. Hanson, A. C. Gossard

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

We demonstrate high-speed manipulation of a few-electron double quantum dot. In the one-electron regime, the double dot forms a charge qubit. Microwaves are used to drive transitions between the (1,0) and (0,1) charge states of the double dot. A local quantum point contact charge detector measures the photon-induced change in occupancy of the charge states. Charge detection is used to measure T1 ∼ 16 ns and also provides a lower bound estimate for T2 *of 400 ps for the charge qubit. In the two-electron regime we use pulsed-gate techniques to measure the singlet-triplet relaxation time for nearly-degenerate spin states. These experiments demonstrate that the hyperfine interaction leads to fast spin relaxation at low magnetic fields. Finally, we discuss how two-electron spin states can be used to form a logical spin qubit.

Original languageEnglish (US)
Pages (from-to)42-46
Number of pages5
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume34
Issue number1-2
DOIs
StatePublished - Aug 2006

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

Keywords

  • Charge qubit
  • Coherent manipulation
  • Rabi oscillation
  • Spin qubit

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