Phys.org January 26, 2023
Electron spins in silicon quantum dots are excellent qubits because they have long coherence times and high gate fidelities, and compatible with advanced semiconductor manufacturing techniques. A team of researchers in the US (University of Rochester, industry) has shown that spin–valley coupling in Si, which drives transitions between states with different spin and valley quantum numbers, enables coherent control of single- and multi-electron spin states without oscillating electromagnetic fields. They demonstrated Rabi oscillations between effective single-spin states in a Si/SiGe double quantum dot that are driven by spin–valley coupling. Together with the exchange coupling between neighbouring electrons, spin–valley coupling also enables universal control of effective two-spin states, driving singlet–triplet and triplet–triplet oscillations that feature coherence times on the order of microseconds. According to the researchers their results establish spin–valley coupling as a promising mechanism for coherent control of qubits based on electron spins in semiconductor quantum dots…read more. TECHNICAL ARTICLE
Experimental set-up. Credit: Nat. Phys. (2023)