A silicon singlet–triplet qubit driven by spin-valley coupling

• Published in: Nature communications 2022-02, Vol.13 (1), p.641-641, Article 641
• Main Authors: Jock, Ryan M., Jacobson, N. Tobias, Rudolph, Martin, Ward, Daniel R., Carroll, Malcolm S., Luhman, Dwight R.
• Format: Article
• Language: English
• Subjects: 639/766/483/2802; 639/925/927/481; Charge density; Decoupling; Electron spin; Electronics industry; Electrons; Frequency drift; Humanities and Social Sciences; LF noise; Logic circuits; MATHEMATICS AND COMPUTING; Metal oxide semiconductors; multidisciplinary; Noise; Orthogonality; Power spectral density; Quantum dots; quantum information; qubits; Qubits (quantum computing); Science; Science (multidisciplinary); Silicon; Spin-orbit interactions; Striplines
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-28302-y

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/ f α dependence consistent with α  ~ 0.7, over 9 orders of magnitude in noise frequency. Spin-orbit coupling in gate-defined quantum dots in silicon metal-oxide semiconductors provides a promising route for electrical control of spin qubits. Here, the authors demonstrate that intervalley spin–orbit interaction enables fast singlet–triplet qubit rotations in this platform, at frequencies exceeding 200MHz.