Abstract
Spin–orbit effects, inherent to electrons confined in quantum dots at a silicon heterointerface, provide a means to control electron spin qubits without the added complexity of on-chip, nanofabricated micromagnets or nearby coplanar striplines. Here, we demonstrate a singlet–triplet qubit operating mode that can drive qubit evolution at frequencies in excess of 200 MHz. This approach offers a means to electrically turn on and off fast control, while providing high logic gate orthogonality and long qubit dephasing times. We utilize this operational mode for dynamical decoupling experiments to probe the charge noise power spectrum in a silicon metal-oxide-semiconductor double quantum dot. In addition, we assess qubit frequency drift over longer timescales to capture low-frequency noise. We present the charge noise power spectral density up to 3 MHz, which exhibits a 1/fα dependence consistent with α ~ 0.7, over 9 orders of magnitude in noise frequency.
Highlights
Spin–orbit effects, inherent to electrons confined in quantum dots at a silicon heterointerface, provide a means to control electron spin qubits without the added complexity of on-chip, nanofabricated micromagnets or nearby coplanar striplines
Qubits based on the spins of electrons confined to gatedefined quantum dots (QDs) in silicon metal-oxidesemiconductor (MOS) structures have developed into a promising platform for quantum information processing
Qubit control techniques demonstrated in silicon MOS have utilized electron spin resonance (ESR) with microwave strip-lines[1,2,6], electric dipole spin resonance (EDSR) using micromagnets[5] or the intrinsic spin–orbit coupling (SOC) at the Si/SiO2 interface[7,8,9]
Summary
Spin–orbit effects, inherent to electrons confined in quantum dots at a silicon heterointerface, provide a means to control electron spin qubits without the added complexity of on-chip, nanofabricated micromagnets or nearby coplanar striplines. This approach offers a means to electrically turn on and off fast control, while providing high logic gate orthogonality and long qubit dephasing times We utilize this operational mode for dynamical decoupling experiments to probe the charge noise power spectrum in a silicon metal-oxide-semiconductor double quantum dot. We utilize the intervalley spin–orbit interaction near the spin-valley hot spot in a silicon MOS QD and demonstrate the ability to drive singlet–triplet rotations in excess of 200 MHz using the intervalley spin–orbit interaction We exploit these fast rotations near the hot spot to enable unique qubit operation with high-speed all-electrical modulation between qubit logic gates and high orthogonality of control axes through electrical control of the valley splitting.
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