Spin qubits in gate-defined silicon quantum dots are receiving increased attention thanks to their potential for large-scale quantum computing. Readout of such spin qubits is done most accurately and scalably via Pauli spin blockade (PSB), however, various mechanisms may lift PSB and complicate readout. In this work, we present an experimental study of PSB in a multi-electron low-symmetry double quantum dot (DQD) in silicon nanowires. We report on the observation of non-symmetric PSB, manifesting as blockaded tunneling when the spin is projected to one QD of the pair but as allowed tunneling when the projection is done into the other. By analyzing the interaction of the DQD with a readout resonator, we find that PSB lifting is caused by a large coupling between the different electron spin manifolds of 7.90 μeV and that tunneling is incoherent. Further, magnetospectroscopy of the DQD in 16 charge configurations, enables reconstructing the energy spectrum of the DQD and reveals the lifting mechanism is energy-level selective. Our results indicate enhanced spin-orbit coupling which may enable all-electrical qubit control of electron spins in silicon nanowires.

门定义硅量子点中的自旋量子位由于其大规模量子计算的潜力而受到越来越多的关注。这种自旋量子位的读出是通过泡利自旋封锁 (PSB) 最准确且可扩展地完成的，但是，各种机制可能会提升 PSB 并使读出复杂化。在这项工作中，我们提出了硅纳米线中多电子低对称性双量子点（DQD）中 PSB 的实验研究。我们报告了对非对称 PSB 的观察，当自旋投射到一对量子点中的一个时，表现为阻塞隧道，但当投射到另一个量子点时，表现为允许隧道。通过分析 DQD 与读出谐振器的相互作用，我们发现 PSB 提升是由 7.90 μeV 的不同电子自旋流形之间的大耦合引起的，并且隧道效应是不相干的。此外，16 种电荷配置的 DQD 的磁谱分析能够重建 DQD 的能谱，并揭示提升机制是能级选择性的。我们的结果表明增强的自旋轨道耦合可以实现硅纳米线中电子自旋的全电量子位控制。