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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
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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 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.

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J. R. Petta, A. C. Johnson, J. M. Taylor, A. Yacoby, M. D. Lukin, C. M. Marcus, M. P. Hanson, A. C. Gossard. 2005-10-06. Charge and spin manipulation in a few-electron double dot. https://doi.org/10.1016/j.physe.2006.02.033

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