Shallow implanted SiC spin qubits used for sensing an internal spin bath and external YIG spins

Silicon vacancy (VSi) color centers in bulk SiC are excellent electron spin qubits. However, most spin based quantum devices require shallow spin qubits, whose dynamics is often different from that of bulk ones. Here, we demonstrate (i) a new method for creating shallow VSi (V2) spin qubits below the SiC surface by low energy ion implantation through a sacrificial SiO2 layer, (ii) that these shallow VSi are dipolar coupled to an electronic spin bath, analysed by Hahn echo decay, dynamical decoupling (DD), and optically pumped pulsed electron-electron double resonance experiments (OP-PELDOR), (iii) that their coherence time increases with cooling of the spin bath (from 55 mu s at 297 K to 107 mu s at 28 K), and that it can be further extended to 220 mu s at 100 K by DD, thus demonstrating their relevance for PELDOR-based quantum sensors and processors. Finally, (iv) external spin sensing is demonstrated by the shift of VSi magnetic resonance lines induced by the dipolar stray magnetic field of a nearby ferrimagnetic YIG film.

Automated summary

A new method has been demonstrated to create shallow silicon vacancy (V2) spin qubits below the surface of SiC through low energy ion implantation. These shallow spin qubits are shown to be dipolar coupled to an electronic spin bath, with their coherence time increasing with cooling of the spin bath and further extended by dynamical decoupling. External spin sensing is also demonstrated through the shift of VSi magnetic resonance lines induced by a nearby ferrimagnetic YIG film's dipolar stray magnetic field.