  Transition metal (TM) defects in silicon carbide (SiC) are a promising
platform in quantum technology, especially because some TM defects emit in the
telecom band. We develop a theory for the interaction of an active electron in
the $D$-shell of a TM defect in SiC with the TM nuclear spin and derive the
effective hyperfine tensor within the Kramers doublets formed by the spin-orbit
coupling. Based on our theory we discuss the possibility to exchange the
nuclear and electron states with potential applications for nuclear spin
manipulation and long-lived nunclear-spin based quantum memories.
