Dipolar spin relaxation of divacancy qubits in silicon carbide

Divacancy spins implement qubits with outstanding characteristics and capabilities in an industrial semiconductor host. On the other hand, there are still numerous open questions about the physics of these important defects, for instance, spin relaxation has not been thoroughly studied yet. Here, we carry out a theoretical study on environmental spin-induced spin relaxation processes of divacancy qubits in the 4H polytype of silicon carbide (4H-SiC). We reveal all the relevant magnetic field values where the longitudinal spin relaxation time T-1 drops resonantly due to the coupling to either nuclear spins or electron spins. We quantitatively analyze the dependence of the T-1 time on the concentration of point defect spins and the applied magnetic field and provide an analytical expression. We demonstrate that dipolar spin relaxation plays a significant role both in as-grown and ion-implanted samples and it often limits the coherence time of divacancy qubits in 4H-SiC.

Automated summary

This study theoretically investigates the spin-induced spin relaxation processes of divacancy qubits in 4H-SiC, revealing the dependence of the longitudinal spin relaxation time T-1 on the concentration of point defect spins and the applied magnetic field. The results demonstrate that dipolar spin relaxation plays a significant role in limiting the coherence time of divacancy qubits in both as-grown and ion-implanted samples.