Extended Data Fig. 5: Single-spin Rabi oscillation pulse sequence and control measurements.
a We prepare the state \(\left\vert {\downarrow }^{+}{\uparrow }^{-}\right\rangle\) by adiabatically separating a singlet state in the presence of ΔEZ. After an evolution period of variable time, te, we reverse the initialization process to map \(\left\vert {\downarrow }^{+}{\uparrow }^{-}\right\rangle\) back to \(\left\vert {S}^{+-}\right\rangle\) for PSB readout. b We prepare \(\left\vert {\uparrow }^{+}{\downarrow }^{-}\right\rangle\) in a similar way, except that we add a ΔEZπ pulse before separating and after recombining the electrons. The initial π pulse rotates the state \(\left\vert {S}^{+-}\right\rangle\) to \(\left\vert {T}_{0}^{+-}\right\rangle\). The \(\left\vert {T}_{0}^{+-}\right\rangle\) state, in turn, evolves to the state \(\left\vert {\uparrow }^{+}{\downarrow }^{-}\right\rangle\) upon adiabatic separation. The readout follows the same steps in reverse, where the adiabatic pulse maps \(\left\vert {\uparrow }^{+}{\downarrow }^{-}\right\rangle\) back to \(\left\vert {T}_{0}^{+-}\right\rangle\) and then the π pulse maps \(\left\vert {T}_{0}^{+-}\right\rangle\) to \(\left\vert {S}^{+-}\right\rangle\). c,d Control measurements at a magnetic field away from the spin funnels, Bz=350 mT, using the pulse sequence in a and the pulse sequence in b, respectively. No oscillations are observed in either case. e Measured single-spin Rabi oscillation near the third spin funnel with Bz=380.8 mT, using the pulse sequence in a. The Rabi frequency is about 15 MHz, and the \({T}_{2}^{* }\) time is about 3 μs, resulting in a quality factor Q ~ 40 − 50, which is close to the typical values obtained using electric-dipole spin resonance in a magnetic field gradient for natural Si devices68.
