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arXiv · 1108.4210

Relaxation and Readout Visibility of a Singlet-Triplet Qubit in an Overhauser Field Gradient

C. Barthel·J. Medford·H. Bluhm·A. Yacoby·C. M. Marcus·M. P. Hanson·A. C. Gossard
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Abstract

Using single-shot charge detection in a GaAs double quantum dot, we investigate spin relaxation time T_1 and readout visibility of a two-electron singlet-triplet qubit following single-electron dynamic nuclear polarization (DNP). For magnetic fields up to 2 T, the DNP cycle is in all cases found to increase Overhauser field gradients, which in turn decrease T_1 and consequently reduce readout visibility. This effect was previously attributed to a suppression of singlet-triplet dephasing under a similar DNP cycle. A model describing relaxation after singlet-triplet mixing agrees well with experiment. Effects of pulse bandwidth on visibility are also investigated.

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C. Barthel, J. Medford, H. Bluhm, A. Yacoby, C. M. Marcus, M. P. Hanson, A. C. Gossard. 2011-08-21. Relaxation and Readout Visibility of a Singlet-Triplet Qubit in an Overhauser Field Gradient. https://doi.org/10.1103/physrevb.85.035306

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