Single Color Center Spin Coherence revealed in Optically Detected Magnetic Resonance of an Ensemble of Silicon Vacancies in SiC

Abstract

We present a quantitative theory for simulating optically detected magnetic resonance (ODMR) measurements of optically-active spin centers using steady-state Lindblad equations. We apply the theory to an experimental ODMR spectrum associated with the negatively-charged silicon vacancy V2 center in 6H-SiC, showing that spin Hamiltonian parameters, optical transition rates, and even coherence times may be extracted, with values consistent with recent literature. Notably the $T_2$ spin coherence time is measurable, not just the $T_2^*$ dephasing time. Furthermore, we simulate the ODMR spectra of a V2 center in isotopically-purified 6H-SiC, and predict an order-of-magnitude narrowing of some, but not all spectral lines compared with natural abundance samples.

Figures (3)

• Figure 1: (a) ODMR spectrum of the V2 silicon vacancy center in 6H-SiC versus magnetic field with a microwave frequency of 9.4 GHz. The simulated spectra is compared to the measurement in KrausH.2014Rqme. (Inset): The ODMR diagram used in our model including the ground and excited state zero-field splittings ($D_{g,e}$), absorption rates ($k_{a}$), spontaneous emission rates ($k_{e}$), and intersystem crossing rates ($k_{1-4}$). (b) ODMR spectrum of the ground resonances $B_{2\pm}$ and $B_{2i\pm}$. (Insets): Energy level diagrams of the transitions associated with $B_{2\pm}$ and $B_{2i\pm}$.
• Figure 2: (a) ODMR spectrum of the excited state resonances $B_{2e\pm}$. (Insets): Energy level diagrams of the transitions associated with $B_{2e\pm}$. (a) ODMR spectrum of the ground state half-field resonances $B_{2h\pm}$. (Insets): Energy level diagrams of the transitions associated with $B_{2h\pm}$.
• Figure 3: (a) The predicted ODMR spectrum of the V2 silicon vacancy center in isotopically-purified and magnetically-homogeneous 6H-SiC versus magnetic field with a microwave frequency of 9.4 GHz. The simulated spectra is compared to the natural abundance measurement in KrausH.2014Rqme for reference. (b) Predicted ODMR spectrum of the ground resonances $B_{2\pm}$ and $B_{2i\pm}$. (b) Predicted ODMR spectrum of the ground state half-field resonances $B_{2h\pm}$.