From: hackbard Date: Wed, 18 Aug 2010 18:03:07 +0000 (+0200) Subject: hopefully basically finished c_i - c_i interaction X-Git-Url: https://hackdaworld.org/gitweb/?a=commitdiff_plain;h=1183554984612f885daa2d87d463bd28d2acca32;p=lectures%2Flatex.git hopefully basically finished c_i - c_i interaction --- diff --git a/posic/publications/defect_combos.tex b/posic/publications/defect_combos.tex index c2bd223..b863fc9 100644 --- a/posic/publications/defect_combos.tex +++ b/posic/publications/defect_combos.tex @@ -236,9 +236,17 @@ Thus, lower migration barriers are expected for pathways resulting in larger sep However, if the increase of separation is accompanied by an increase in binding energy, this difference is needed in addition to the activation energy for the respective migration process. Configurations, which exhibit both, a low binding energy as well as targeting transitions with low activation energies are, thus, most probable C$_{\text{i}}$ complex structures. On the other hand, if elevated temperatures enable migrations with huge activation energies, the comparably small differences in configurational energy can be neglected resulting in an almost equal occupation of these configurations. -In both cases the configuration yielding a binding energy of \unit[-2.25]{eV} is promising since it constitutes the second most energetically favorable structure, exhibits a low migration barrier of transition starting from more separated defect structures and +In both cases the configuration yielding a binding energy of \unit[-2.25]{eV} is promising. +First of all it constitutes the second most energetically favorable structure. +Secondly, a migration path with a barrier as low as \unit[?.?]{eV} exists starting from a configuration of largely separated defects exhibiting a low binding energy (\unit[-1.88]{eV}). +The migration barrier and correpsonding structures are shown in Fig.~\ref{fig:188-225}. % 188 - 225 transition in progress -is represented four times (two times more often than the ground state configuration) within the investigated configuration space. +\begin{figure} +\includegraphics[width=\columnwidth]{188-225.eps} +\caption{Migration barrier and structures of the transition of a C$_{\text{i}}$ \hkl[0 -1 0] DB at position 5 (left) into a C$_{\text{i}}$ \hkl[1 0 0] DB at position 1 (right). An activation energy of \unit[?.?]{eV} is observed.} +\label{fig:188-225} +\end{figure} +Finally, this type of defect pair is represented four times (two times more often than the ground state configuration) within the investigated configuration space. The latter is considered very important for high temperatures, which is accompanied by an increase in the entropic contribution to structure formation. Thus, C agglomeration indeed is expected but only a low probability is assumed for C clustering by thermally activated processes with regard to the considered period of time. % ?!? @@ -267,6 +275,7 @@ The binding energy of these configurations with respect to the C-C distance is p \label{fig:dc_110} \end{figure} The interaction is found to be proportional to the reciprocal cube of the C-C distance for extended separations of the C$_{\text{i}}$ and saturates for the smallest possible separation, i.e. the ground state configuration. +Not considering the previously mentioned elevated barriers for migration an attractive interaction between the C$_{\text{i}}$ defects indeed is detected with a capture radius that clearly exceeds the \unit[1]{nm} mark. \begin{table} \begin{ruledtabular}