Spin-orbit coupling and operation of multi-valley spin qubits

Understand

Spin qubits composed of either one or three electrons are realized in a quantum dot formed at a Si/SiO_2-interface in isotopically enriched silicon.

• Using pulsed electron spin resonance, we perform coherent control of both types of qubits, addressing them via an electric field dependent g-factor.
• We perform randomized benchmarking and find that both qubits can be operated with high fidelity.
• Surprisingly, we find that the g-factors of the one-electron and three-electron qubits have an approximately linear but opposite dependence as a function of the applied dc electric field.