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 observation of a new, highly prevalent PSB-lifting mechanism in a silicon double quantum dot due to incoherent tunneling between different spin manifolds. Through dispersively-detected magnetospectroscopy of the double quantum dot in 16 charge configurations, we find the mechanism to be energy-level selective and non-reciprocal for neighbouring charge configurations. Additionally, using input-output theory we report a large coupling of different electron spin manifolds of 7.90 μeV, the largest reported to date, indicating an enhanced spin-orbit coupling which may enable all-electrical qubit control.
@article{arxiv.2110.09842,
title = {Non-reciprocal Pauli Spin Blockade in a Silicon Double Quantum Dot},
author = {Theodor Lundberg and David J. Ibberson and Jing Li and Louis Hutin and José C. Abadillo-Uriel and Michele Filippone and Benoit Bertrand and Andreas Nunnenkamp and Chang-Min Lee and Nadia Stelmashenko and Jason W. A. Robinson and Maud Vinet and Lisa Ibberson and Yann-Michel Niquet and M. Fernando Gonzalez-Zalba},
journal= {arXiv preprint arXiv:2110.09842},
year = {2024}
}