The Dispersive Signature of Pauli Spin Blockade

Pauli Spin Blockade (PSB) serves as an efficient means of mapping the spin state of an electron or hole to the charge state of a quantum dot network. This spin-to-charge conversion is a key ingredient for quantum computation based on semiconductor spins, as it allows for efficient spin readout and initialisation with high-fidelity even at elevated temperatures [Camenzind et al. Nat. Electron. 5 (2022)]. Different readout schemes have been developed, including direct-current measurements, capacitively coupled dedicated sensors like single-electron transistors and gate-dispersive charge sensing. The gate-dispersive approach holds great promise due to the relaxed requirements for additional on-chip nanostructures, enabling single-shot spin readout in dense qubit arrays and 1D systems whose architecture prevents the implementation of nearby sensor dots. PSB manifests in different ways, depending on the particular readout scheme chosen and can be tuned to implement singlet/triplet or parity readout [Seedhouse et al. PRX Quantum 2 (2021)].

Here, we report on the direct observation of PSB in a gate-dispersively sensed hole double quantum dot [Eggli et al, arXiv, 2303.029339]. We investigate the dependence of the dispersive features on externally applied magnetic fields and theoretically model the qubit system. Our results present a route towards high-fidelity gate-dispersive spin readout.