started c mobility

diff --git a/posic/publications/sic_prec.tex b/posic/publications/sic_prec.tex
index 84c24d5..fe8ddaa 100644 (file)
--- a/posic/publications/sic_prec.tex
+++ b/posic/publications/sic_prec.tex
@@ -192,9 +192,16 @@ Unexpectedly, the structure of a Si$_{\text{i}}$ \hkl<1 1 0> DB and a next neigh
 This is attributed to an effective reduction in strain enabled by the respective combination.
 Thus, a proper description with respect to the relative energies of formation is assumed for the EA potential.
 
-\subsection{Mobility}
+\subsection{Carbon mobility}
+
+To accurately model the SiC precipitation, which involves the agglomeration of C, a proper description of the migration process of the C impurity is required.
+As shown in a previous study\cite{zirkelbach10a} quantum-mechanical results properly describe the C$_{\text{i}}$ \hkl<1 0 0> DB diffusion resulting in a migration barrier height of \unit[0.90]{eV} excellently matching experimental values of \unit[0.70-0.87]{eV}\cite{lindner06,tipping87,song90} and, for this reason, reinforcing the respective migration path as already proposed by Capaz et~al.\cite{capaz94}.
+However, it turned out that the description fails if the EA potential is used, which overestimates the migration barrier (\unit[2.2]{eV}) by a factor of 2.4.
+In addition a different diffusion path is found to exhibit the lowest migration barrier.
+The proposed path involves the C$_{\text{i}}$ BC configuration, which, however, was found to be unstable relaxing into the C$_{\text{i}}$ \hkl<1 1 0> DB configuration.
+
+
 
-To accurately model the SiC precipitation the agglomeration of C the activation energies for the C migration have to be reproduced correctly.
 
 A measure for the mobility of the interstitial carbon is the activation energy for the migration path from one stable position to another.
 The stable defect geometries have been discussed in the previous subsection.