Coherent mechanical driving of spin ensembles in 4H-SiC using a gaussian surface acoustic wave resonator*

Silicon carbide (SiC) has recently emerged as a promising host material for spin qubits. In particular, divacancies and silicon vacancies in 4H-SiC have been shown to have similar optical and spin properties to the nitrogen vacancy center in diamond. SiC also provides wafer-scale growth and mature fabrication processes, as well as being a piezoelectric material allowing for design of electromechanical devices. Here we demonstrate design, fabrication and characterization of a gaussian surface acoustic wave resonator (SAW) using a sputtered AlN epilayer on top of 4H-SiC, which is used to drive strain-induced coherent mechanical control of divacancy spin ensembles near the surface. This enables demonstration of Autler-Townes splitting and coherent Rabi driving on all c-axis (hh, kk, and PL6) defects. We further utilize the Autler-Townes effect to map the gaussian SAW mode shape, measuring a transverse beam waist of only 40 µm full width at half maximum (12 µm wavelength). This work provides the basis for further spin-mechanical hybrid systems, and in particular toward applications such as quantum communication and transduction.