High-fidelity control and unprecedented long dephasing times in silicon-based single spin qubits have recently confirmed the prospects of solid-state quantum computation. We investigate the feasibility of using a micro-magnet stray field for all-electrical, addressable spin qubit control in a Si/SiGe double quantum dot. For a micro-magnet geometry optimized for high Rabi-frequency, addressability, and robustness to fabrication misalignment as previously demonstrated by Yoneda et al. [Phys. Rev. Lett. 113, 267601 (2014)], we simulate the qubit decoherence due to magnetic stray-field fluctuations, which may dominate in nuclear spin-free systems, e.g., quantum dots in Si/SiGe, Si-MOS structures and (bilayer) graphene. With calculated Rabi-frequencies of 15 MHz, a qubit addressability error below 10−3 is achievable. Magnetic fluctuations from a micro-magnet limits the spin relaxation time to T1 ≳ 3 s, while pure spin dephasing is negligible. Our results show that micro-magnets are a promising tool for spin qubit computation in nuclear spin-free systems.
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Research Article| May 18 2015
Simulation of micro-magnet stray-field dynamics for spin qubit manipulation
R. Neumann, L. R. Schreiber; Simulation of micro-magnet stray-field dynamics for spin qubit manipulation. J. Appl. Phys. 21 May 2015; 117 (19): 193903. https://doi.org/10.1063/1.4921291
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