Electrically controlled strain tuning of spin defects in a hybrid 4H-silicon carbide-on-lithium niobate integrated platform

We realized a wafer-scale hybrid quantum platform by integrating 4H-silicon carbide (SiC) thin films with lithium niobate-on-insulator (LNOI) substrates. Wafer bonding combined with precision grinding established a void-free interface to harness the strong piezoelectric response of LN for efficient strain transfer. By generating controlled local strain via surface electrodes, the optically detected magnetic resonance (ODMR) frequency of the negatively charged silicon vacancy (V2) centers was tuned by 1.36 MHz. The applied strain significantly enhanced spin properties, improving the spin readout contrast by roughly 30% while increasing the inhomogeneous dephasing time ( T 2 * ) by 75% and the intrinsic coherence time ( T 2 ) by nearly 50%. These results position the 4H-SiC-on-LNOI architecture as an integrable and strain-controllable platform for high-sensitivity quantum sensing applications.