Abstract

For quantum spintronics and vector sensing of electric and magnetic fields long-lived electronic spins in solid state are promising systems. Divacancy defects (missing carbon and silicon atoms) in silicon carbide have such spin states, with sharp optical transitions and other properties comparable to the exceptionally successful nitrogen-vacancy defect in diamond. We report experiments on divacancy ensembles in 4H-SiC that investigate all-optical addressing of spin states [1]. Our magneto-spectroscopy results identify the spin S=1 structure of the ground and as yet elusive excited state, and reveal a role for non-radiative decay via a singlet state (known as intersystem crossing). We use these results for demonstrating all-optical coherent population trapping of spin states (see Fig. 1a inset), for divacancies which have particular orientations in the SiC crystal, a key ingredient for homogeneous all-optical spin control. A pronounced sharp quenching in the photoluminescence excitation (PLE) light at two-photon resonance is a signature of destructive quantum interference of the excited state dynamics, which results in coherent superposition of the ground state.

© 2015 IEEE