-\begin{figure}
-\begin{minipage}[t]{0.32\columnwidth}
-\underline{Tetrahedral}\\
-\includegraphics[width=\columnwidth]{tet.eps}
-\end{minipage}
-\begin{minipage}[t]{0.32\columnwidth}
-\underline{Hexagonal}\\
-\includegraphics[width=\columnwidth]{hex.eps}
-\end{minipage}
-\begin{minipage}[t]{0.32\columnwidth}
-\underline{\hkl<1 0 0> dumbbell}\\
-\includegraphics[width=\columnwidth]{100.eps}
-\end{minipage}\\
-\begin{minipage}[t]{0.32\columnwidth}
-\underline{\hkl<1 1 0> dumbbell}\\
-\includegraphics[width=\columnwidth]{110.eps}
-\end{minipage}
-\begin{minipage}[t]{0.32\columnwidth}
-\underline{Substitutional}\\[0.05cm]
-\includegraphics[width=\columnwidth]{sub.eps}
-\end{minipage}
-\begin{minipage}[t]{0.32\columnwidth}
-\underline{Bond-centered}\\
-\includegraphics[width=\columnwidth]{bc.eps}
-\end{minipage}
-\caption{Configurations of carbon point defects in silicon. The silicon/carbon atoms and the bonds (only for the interstitial atom) are illustrated by yellow/grey spheres and blue lines. Bonds are drawn for atoms located within a certain distance and do not necessarily correspond to chemical bonds.}
-\label{fig:defects}
-\end{figure}
+Although discrepancies exist, both methods depict the correct order of the formation energies with regard to C defects in Si.
+Substitutional C (C$_{\text{s}}$) constitutes the energetically most favorable defect configuration.
+Since the C atom occupies an already vacant Si lattice site, C$_{\text{s}}$ is not an interstitial defect.
+The quantum-mechanical result agrees well with the result of another ab initio study\cite{dal_pino93}.
+Clearly, the empirical potential underestimates the C$_{\text{s}}$ formation energy.
+The C interstitial defect with the lowest energy of formation has been found to be the C-Si \hkl<1 0 0> interstitial dumbbell (C$_{\text{i}}$ \hkl<1 0 0> DB), which, thus, constitutes the ground state of an additional C impurity in otherwise perfect c-Si.
+This finding is in agreement with several theoretical\cite{burnard93,leary97,dal_pino93,capaz94} and experimental\cite{watkins76,song90} investigations.
+Astonishingly EA and DFT predict almost equal formation energies.
+There are, however, geometric differences with regard to the DB position within the tetrahedron spanned by the four next neighbored Si atoms, as already reported in a previous study\cite{zirkelbach10a}.
+Since the energetic description is considered more important than the structural description minor discrepancies of the latter are assumed non-problematic.
+This second most favorable configuration is the C$_{\text{i}}$ \hkl<1 1 0> DB followed by the C$_{\text{i}}$ bond-centered (BC) configuration.
+For both configurations EA overestimates the energy of formation by approximately \unit[1]{eV} compared to DFT.
+Thus, nearly the same difference in energy has been observed for these configurations in both methods.
+However, we have found the BC configuration to constitute a saddle point within the EA description relaxing into the \hkl<1 1 0> configuration.
+Due to the high formation energy of the BC defect resulting in a low probability of occurence of this defect, the wrong description is not posing a serious limitation of the EA potential.
+A more detailed discussion of C defects in Si modeled by EA and DFT including further defect configurations are presented in a previous study\cite{zirkelbach10a}.
+