Gate-based single-shot spin readout in a silicon-MOS double quantum dot

A scalable error-corrected quantum processor will require repeated error detection across its constituent qubits. For semiconductor quantum dots, the requisite single-shot spin readout is presently performed using on-chip charge sensors. However, as the number of qubits is increased, this approach becomes impractical due to the complexity of the charge sensors, combined with the required proximity to the quantum dots. Alternatively, spin readout can proceed by combining Pauli-spin blockade with dispersive gate-based sensing, requiring only the gate electrodes that also define the quantum dots. Here, we detect single electron tunnelling in a silicon-MOS double quantum dot and demonstrate that gate-based sensing can be used to read out the electronic spin state in a single shot, with an average readout fidelity of 73%. The result demonstrates a key step towards the readout of many spin qubits in parallel, using a compact gate design that will be needed for a large-scale semiconductor quantum processor.