The substitutional C is located next to the lattice site shared by the \hkl<1 1 0> Si self-interstitial along the \hkl<1 -1 0> direction.
Thus, the compressive stress along \hkl<1 1 0> of the Si \hkl<1 1 0> interstitial is not compensated but intensified by the tensile stress of the substitutional C atom, which is no longer loacted along the direction of stress.
+{\color{red}Todo: Erhart/Albe calc for most and less favorable configuration!}
+
{\color{red}Todo: Mig of C-Si DB conf to or from C sub + Si 110 in progress.}
\section{Migration in systems of combined defects}