Implications of the Spin-Orbit Effect for Singlet-Triplet Qubit Operation

Spin-orbit effects in silicon have long been considered of minor importance for the operation of spin qubits. In this work, we use a silicon MOS double quantum dot singlet-triplet qubit as a sensitive probe of the spin-orbit effect. We first show that a strong magnetic field enables rotations between the singlet S and triplet T₀, an effect which amounts to an effective g-factor difference between the two quantum dots. Two-axis control and single shot readout of the qubit is used to study AC resonant control and achieve few microsecond Rabi flip times. Secondly, we investigate a different effect of the spin-orbit interaction on the S-T₋ transition and its impact on schemes like dynamic nuclear polarization. Our results shed light on the implications of spin-orbit interaction for the operation of spin qubits in silicon.

This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the DOE’s National Nuclear Security Administration under contract DE-NA0003525.