Single-Shot Single-Gate rf Spin Readout in Silicon

For solid-state spin qubits, single-gate rf readout can minimize the number of gates required for scale-up since the readout sensor can integrate into the existing gates used to manipulate the qubits. However, state-of-the-art topological error correction codes benefit from the ability to resolve the qubit state within a single shot, that is, without repeated measurements. Here, we demonstrate single-gate, single-shot readout of a singlet-triplet spin state in silicon, with an average readout fidelity of 82.9% at 3.3 kHz measurement bandwidth. We use this technique to measure a triplet T- to singlet S0 relaxation time of 0.62 ms in precision donor quantum dots in silicon. We also show that the use of rf readout does not impact the spin lifetimes (S0 to T- decay remained approximately 2 ms at zero detuning). This establishes single-gate sensing as a viable readout method for spin qubits.