Spin Relaxation in Si/SiGe Quantum Dot Devices with Micromagnets

ORAL

Abstract

Recent quantum control experiments in Si/SiGe quantum dots utilizing a micromagnet for electrically driven spin resonance have reported spin relaxation times (T1) ranging from 4 ms to more than 50 ms [1,2]. These T1 times are shorter than those obtained on samples without micromagnets, which suggests that the presence of the micromagnet is limiting T1 [3,4]. We measure T1 in a Si/SiGe device incorporating a micromagnet up to a magnetic field of 6 T. We find a saturation of T1 at low fields, evidence of a valley relaxation hotspot, and a soft B3 field dependence above 2 T. These measurements indicate that the spin-orbit coupling induced by the micromagnet causes otherwise suppressed relaxation channels to dominate and limit qubit performance.

[1] Zajac et al., arXiv:1708.03530
[2] Watson et al., arXiv:1708.04214
[3] Hayes et al., arXiv:0908.0173
[4] Yang et al., Nature Comm. 4 2069 (2013)

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Presenters

  • Felix Borjans

    Physics, Princeton Univ., Department of Physics, Princeton University

Authors

  • Felix Borjans

    Physics, Princeton Univ., Department of Physics, Princeton University

  • David Zajac

    Physics, Princeton University, Physics, Princeton Univ., Department of Physics, Princeton University

  • Jason Petta

    Physics, Princeton University, Princeton University, Department of Physics, Princeton University, Physics, Princeton Univ.