Superhyperfine interaction and spin-lattice relaxation of an interstitial iron impurity in silicon

We calculate, for the first time to our knowledge, the superhyperfine coupling constant at ${}_{}{}^{29}{}_{}{}^{}\mathrm{Si}$ nuclei in Si:${\mathrm{Fe}}_1^0$ and give a reasonable physical picture explaining the electron-nuclear double resonance data. we predict the spin-lattice relaxation time ($T_1$) taking into account the modulation of the spin-orbit coupling by lattice vibrations. The theoretically predicted ($T_1$ ${)}_D$ due to the direct (D) process and ($T_1$ ${)}_R$ due to Raman (R) process are (1/$T_1$ ${)}_D$≃0.1406$H^2$T and (1/$T_1$ ${)}_R$≃1. 512×${10}^{\mathrm{-}11}$ $T^7$ (in inverse seconds) for temperatures lower than 50 K.