Abstract: Silicon-based single-electron spin qubits commonly use micromagnets to create an artificial spin orbit coupling (SOC) for Electric Dipole Spin Resonance (EDSR); however, this approach faces scalability challenges. Previously, it has been shown that the Wiggle Well may sufficiently enhance the otherwise weak SOC in the conduction band of Si, allowing for implementation of a strong EDSR protocol; previous calculations indicate that Rabi frequencies exceeding 500MHz/T may be possible [1]. However, SiGe random-alloy disorder causes spatial variations that have not been fully accounted for in these calculations. In this work, we show that alloy disorder gives rise to two main effects relevant for EDSR: the generation of a strong valley dipole (providing an additional EDSR mechanism), and randomization of valley parameters (providing a position-dependent Rabi frequency). We find that the valley-dipole contribution to the Rabi frequency is particularly pronounced in the low-valley-splitting regime. Additionally, we incorporate charge noise effects and compute the position-dependent T2,Rabi time, the dephasing rate, and the quality factor, finding quality factors of the order of 103 . Finally, we identify dephasing-protected ‘sweet spots’ where the qubit is resilient to charge noise.”
[1] B. D. Woods, et al., Phys. Rev. B 107, 035418 (2023)