A silicon metal-oxide-semiconductor electron spin-orbit qubit

Abstract

The silicon metal-oxide-semiconductor (MOS) material system is a technologically important implementation of spin-based quantum information processing. However, the MOS interface is imperfect leading to concerns about 1/f trap noise and variability in the electron g-factor due to spin–orbit (SO) effects. Here we advantageously use interface–SO coupling for a critical control axis in a double-quantum-dot singlet–triplet qubit. The magnetic field-orientation dependence of the g-factors is consistent with Rashba and Dresselhaus interface–SO contributions. The resulting all-electrical, two-axis control is also used to probe the MOS interface noise. The measured inhomogeneous dephasing time, , of 1.6 μs is consistent with 99.95% 28Si enrichment. Furthermore, when tuned to be sensitive to exchange fluctuations, a quasi-static charge noise detuning variance of 2 μeV is observed, competitive with low-noise reports in other semiconductor qubits. This work, therefore, demonstrates that the MOS interface inherently provides properties for two-axis qubit control, while not increasing noise relative to other material choices.

Semiconductor quantum computation

“…is the energy of exchange splitting of and , where the detuning denotes the electrochemical potential difference of different charge occupation states. And is the Zeeman energy difference of two spins, which may be caused by different g-factor [63], i.e. , or magnetic field gradient [64,65], i.e.…”

Hyperfine-assisted decoherence of a phosphorus nuclear-spin qubit in silicon

“…23 suggests that electrical control of the nuclear-spin qubit should be possible either by relying on an inhomogeneous magnetic field (artificial spin-orbit interaction), or by relying on intrinsic spin-orbit interaction. In a simple phenomenological picture, spin-orbit interaction can influence the dot-donor system in two ways; both effects have been observed in silicon double quantum dots [37][38][39][40] . On the one hand, it renormalizes the g-factor (with few percents), potentially making it anisotropic and different at the donor and in the dot.…”

Is all-electrical silicon quantum computing feasible in the long term?

“…Starting from these considerations, hybrid qubits based on three electrons in a double quantum dot provides a balanced compromise among fabrication, tunability, fast gate operations, manipulation and scalability [48]. enables much faster gate operations than using ac magnetic fields, inhomogeneous dc magnetic fields or mechanisms based on spinorbit coupling [49,50,51]. The use of oscillating magnetic or electrical fields or quasi-static Zeeman field gradient, which is mandatory in singlet-triplet qubits, is here unnecessary.…”