Spin-blockade and state lifetimes of many-hole spin states in silicon quantum dots

Hole spins in silicon quantum dots (QDs) are a promising candidate for fault-tolerant quantum computing. To achieve the high-fidelity readout and high coherence required for fault tolerance, the evaluation of spin-blockade and state lifetimes is important because they can limit the qubit fidelities. In this study, we characterize these two figures of merit of many-hole qubits in silicon QDs. We report a spin-blockade lifetime of 5.1 mu s, which is comparable with the values reported previously, and a spin-state lifetime of 0.91 ms, which is longer than the one measured in a few-hole silicon QD in a previous study. We furthermore provide insights into a many-hole spin state based on the estimated tunneling rate ratio.