Manifestations of electron-nuclear interactions in the high-frequency ENDOR/ODMR spectra for triplet Si-C divacancies in $^{13}$C-enriched SiC

The frequencies of electron-nuclear interactions with $^{13}$C and $^{29}Si$ nuclei on remote coordination spheres are determined in triplet spin centers in the form of neutral V$_{\text{Si}}$-V$_{\text{C}}$ divacancies in a silicon carbide crystal of the hexagonal polytype 6H-SiC enriched tenfold in the 13C isotope. High-frequency electron-nuclear double resonance and optically detected magnetic resonance under conditions of optical alignment of spins are used. Oscillations of the electron spin density on $^{29}$Si and $^{13}$C nuclei are found. Nuclear magnetic resonance transitions at Larmor and close-to-Larmor frequencies of $^{13}$C and $^{29}$Si cause giant changes in the populations of spin sublevels with the transformation of these resonances into electron paramagnetic resonance and optical signals.