Probing spin-phonon interactions in silicon carbide with Gaussian acoustics

TL;DR

This paper investigates spin-phonon interactions in silicon carbide using Gaussian acoustics, revealing strain effects, spin-mechanical coupling, and enabling all-optical control of spin states for quantum applications.

Contribution

It introduces a novel Gaussian focusing technique for surface acoustic waves in SiC and provides new insights into spin-strain coupling and all-optical spin control.

Findings

Gaussian focusing of surface acoustic waves achieved in SiC

Direct nanoscale strain measurement via X-ray diffraction

Demonstration of all-optical acoustic resonance detection

Abstract

Hybrid spin-mechanical systems provide a platform for integrating quantum registers and transducers. Efficient creation and control of such systems require a comprehensive understanding of the individual spin and mechanical components as well as their mutual interactions. Point defects in silicon carbide (SiC) offer long-lived, optically addressable spin registers in a wafer-scale material with low acoustic losses, making them natural candidates for integration with high quality factor mechanical resonators. Here, we show Gaussian focusing of a surface acoustic wave in SiC, characterized by a novel stroboscopic X-ray diffraction imaging technique, which delivers direct, strain amplitude information at nanoscale spatial resolution. Using ab initio calculations, we provide a more complete picture of spin-strain coupling for various defects in SiC with C3v symmetry. This reveals the importance of shear for future device engineering and enhanced spin-mechanical coupling. We demonstrate all-optical detection of acoustic paramagnetic resonance without microwave magnetic fields, relevant to sensing applications. Finally, we show mechanically driven Autler-Townes splittings and magnetically forbidden Rabi oscillations. These results offer a basis for full strain control of three-level spin systems.