Global coherent spin control of a SiMOS spin qubit using a 3D KTaO3 dielectric resonator*

As spin qubit numbers are growing, novel scalable control mechanisms become crucial for large-scale qubit architectures. One promising approach to deliver homogeneous oscillating magnetic field over macroscopic length-scales is the use of 3D dielectric resonators. KTaO3 resonators have high permittivity at cryogenic temperatures, and have demonstrated fast and coherent control of spins in NV ensembles and single spin control in SiMOS quantum dots [1-3]. In this latter demonstration, charge noise originating from the Pd/ALD AlOx gate stack limited spin coherence, while electric coupling to metallic gate structures introduced unwanted microwave current loops impacting resonator quality factor and achievable driving speeds. Here, we will present our latest results on KTaO3 global spin control using a modified SiMOS spin qubit design with an optimised Al/thermally grown AlOx gate stack. Removing current loops identified by finite element simulations from the design, the measured resonator quality factor of 1200 improved by 50% compared to our previous generation device. Next to the latest results on global spin control, limiting factors of the resonator-device design will be discussed. This work highlights the promise of dielectric resonators for global spin control in large-scale spin qubit arrays.