Quantum Dots Array on Ultra-Thin SOI Nanowires with Ferromagnetic Cobalt Barrier Gates for Enhanced Spin Qubit Control

Abstract

In this work we propose and demonstrate the integration of ferromagnetic nanosized cobalt barrier gates in quantum dots arrays on FD-SOI nanowires. This innovative structure enhances both driving and addressability, while minimizing decoherence fields for electron spin qubits. Charge noise spectra show $sub-10-^6 e^2Hz-^1$ values at 1Hz, demonstrating a low- noise impact from Co gates. Our double dot experimental data show stable quantum confinement at 10mK and full multi-gate FET functionality. Based on calibrated magnetic simulations, we investigate and discuss the advantages of exploiting simultaneously electrical and ferromagnetic properties of gates. The record small achieved dot-magnet distance is below 10nm, with a footprint of the magnetic gates of 30x70nm2 on dots area, the smallest reported to date on a qubit structure, with a Rabi frequency of 282MHz and qubit addressability of 1.069GHz. This novel architecture paves the way to large-scale integration of qubits arrays with unprecedented magnetic control.