Single-shot readout and microwave control of an electron spin in silicon

The electron spin of a donor in silicon is an excellent candidate for a solid-state qubit. It is known to have very long coherence and relaxation times in bulk [1], and several architectures have been proposed to integrate donor spin qubits with classical silicon microelectronics [2]. Here we show the first experimental proof of single-shot readout of an electron spin in silicon. The device consists of implanted phosphorus donors, tunnel-coupled to a silicon Single-Electron Transistor (SET), where the SET island is used as a reservoir for spin-to-charge conversion [3]. The large charge transfer signals allow readout fidelity $>90${\%} with 3 $\mu $s response time. By measuring the occurrence of excited spin states as a function of wait time, we find spin lifetimes $(T_{1})$ up to $\sim $~6 s at $B = 1.5$~T, and a magnetic-field dependence $T_{1}^{-1} \propto B^{5}$ consistent with that of phosphorus donors in silicon [4]. In a subsequent experiment we have integrated the single-shot spin readout device with an on-chip microwave transmission line for coherent control of the electron spin. We have detected the spin resonance of a single electron, and observed two hyperfine-split resonance lines, consistent with Stark-shifted coupling to the $^{31}$P nuclear spin. Further experiments are underway to demonstrate coherent spin control and observe Rabi oscillations. This demonstrates the microwave control of a single spin, combined -- for the first time in the same experiment -- with electrically detected single-shot spin readout. \newline [1] A. M. Tyryshkin \textit{et al}., Phys. Rev. B \textbf{68}, 193207 (2003). \newline [2] L. C. L. Hollenberg \textit{et al}., Phys. Rev. B. \textbf{74}, 045311 (2006). \newline [3] A. Morello \textit{et al}., Phys. Rev. B \textbf {80}, 081307(R) (2009). \newline [4] A. Morello \textit{et al}., Nature \textbf{467}, 687 (2010).