Identification of acoustically induced spin resonances of Si vacancy centers in 4H-SiC

The long-lived and optically addressable spin states of silicon vacancies ($\mathrm{V}_\mathrm{Si}$) in 4H-SiC make them promising qubits for quantum communication and sensing. These color centers can be created in both the hexagonal (V1) and in the cubic (V2) local crystallographic environments of the 4H-SiC host. While the spin of the V2 center can be efficiently manipulated by optically detected magnetic resonance at room temperature, spin control of the V1 centers above cryogenic temperatures has so far remained elusive. Here, we show that the dynamic strain of surface acoustic waves can overcome this limitation and efficiently excite magnetic resonances of V1 centers up to room temperature. Based on the width and temperature dependence of the acoustically induced spin resonances of the V1 centers, we attribute them to transitions between spin sublevels in the excited state. The acoustic spin control of both kinds of $\mathrm{V}_\mathrm{Si}$ centers in their excited states opens new ways for applications in quantum technologies based on spin-optomechanics.