Barthel, CMedford, James ReddingBluhm, H.Yacoby, AmirMarcus, CHanson, M. P.Gossard, A. C.2014-04-252012Barthel, C., J. Medford, H. Bluhm, A. Yacoby, C. M. Marcus, M. P. Hanson, and A. C. Gossard. 2012. “Relaxation and Readout Visibility of a Singlet-Triplet Qubit in an Overhauser Field Gradient.” Phys. Rev. B 85 (3) (January).1098-01211550-235Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:12111382Using single-shot charge detection in a GaAs double quantum dot, we investigate spin relaxation time (T1) 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 T1 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.en-USJournal Article2014-04-2510.1103/physrevb.85.035306