Spin Structure and Resonant Driving of Spin-1/2 Defects in SiC

Transition metal (TM) defects in silicon carbide (SiC) have favorable spin coherence propertiesand are suitable as spin-photon interfaces for quantum communication. We model defects that have one active electron with spin 1/2 in a d-orbital subspace. The spin structure, as well as the magnetic and optical (electric) resonance properties of the active electron due to the interplay of the crystal potential and spin-orbit coupling are described by a general model derived using group theory. We employ a Schrieffer-Wolff transformation to identify the selection rules within the first and second order in the spin-orbit coupling. The resulting effective Hamiltonian links the g-tensor to the spin-orbit coupling and describes the dependence of the Rabi frequency on the direction of the static and driving field. This theoretical description can be instrumental to perform and optimize spin control in TM defects.