From: hackbard <hackbard@sage.physik.uni-augsburg.de>
Date: Wed, 11 Aug 2010 16:52:15 +0000 (+0200)
Subject: c-c along 110
X-Git-Url: https://hackdaworld.org/gitweb/?a=commitdiff_plain;h=1c018be83b66c3b9284764c041ca8a5d2347a4df;p=lectures%2Flatex.git

c-c along 110
---

diff --git a/posic/publications/defect_combos.tex b/posic/publications/defect_combos.tex
index 5315e09..0cfc29f 100644
--- a/posic/publications/defect_combos.tex
+++ b/posic/publications/defect_combos.tex
@@ -212,29 +212,49 @@ The two C atoms form a strong C-C bond, which is responsible for the large gain
 Investigating migration barriers enables to predict the probability of formation of the thermodynamic ground state defect complex by thermally activated diffusion processes.
 High activation energies are necessary for the migration of low energy configurations, in which the C atom of the second DB is located in the vicinity of the initial DB.
 The transition of the configuration, in which the second DB is of the $\langle 0 1 0\rangle$ type at position 2 (\unit[-1.90]{eV}) into a $\langle 0 1 0\rangle$-type DB at position 1 (\unit[-2.39]{eV}) for instance, revealed a barrier height of more than \unit[4]{eV}.
-Low barriers are only expected from energetically less favorable configurations, e.g. the configuration of the $\langle -1 0 0\rangle$ DB located at position 2.
-A migration barrier of \unit[?.?]{eV} 
+Low barriers do only exist from energetically less favorable configurations, e.g. the configuration of the $\langle -1 0 0\rangle$ DB located at position 2 (\unit[-0.36]{eV}).
+An activation energy of only \unit[?.?]{eV} is necessary for the transition into the ground state configuration.
 %  strange mig from -190 -> -2.39 (barrier > 4 eV)
 % C-C migration -> idea:
 %  mig from low energy confs has extremely high barrier!
 %  low barrier only from energetically less/unfavorable confs (?)! <- prove!
 %  => low probability of C-C clustering ?!?
 Since thermally activated C clustering is, thus, only possible by traversing energetically unfavored configurations, mass C clustering is not expected.
-
+% ?!?
 % look for precapture mechnism (local minimum in energy curve)
+% also: plot energy all confs with respect to C-C distance
+%       maybe a pathway exists traversing low energy confs ?!?
+
+The binding energies of the energetically most favorable configurations with the seocnd DB located along the $\langle 1 1 0\rangle$ direction and resulting C-C distances of the relaxed structures are summarized in Table~\ref{table:dc_110}.
+\begin{table}
+\begin{ruledtabular}
+\begin{tabular}{l c c c c c c }
+ & 1 & 2 & 3 & 4 & 5 & 6 \\
+\hline
+ $E_{\text{b}}$ [eV] & -2.39 & -1.88 & -0.59 & -0.31 & -0.24 & -0.21 \\
+C-C distance [nm] & 0.14 & 0.46 & 0.65 & 0.86 & 1.05 & 1.08 
+\end{tabular}
+\end{ruledtabular}
+\caption{Binding energies $E_{\text{b}}$ and C-C distance of energetically most favorable C$_{\text{i}}$ $\langle 1 0 0\rangle$-type defect pairs separated along bonds in $\langle 1 1 0\rangle$ direction.}
+\label{table:dc_110}
+\end{table}
+The binding energy of these configurations with respect to the C-C distance is plotted in Fig.~\ref{fig:dc_110}
+\begin{figure}
+\includegraphics[width=\columnwidth]{db_along_110_cc_n.ps}
+\caption{Minimum binding energy of dumbbell combinations separated along $\langle 1 1 0\rangle$ with respect to the C-C distance.}
+\label{fig:dc_110}
+\end{figure}
 
-% mattoni2002: c_i c_i attraction basin not explored, too wide paramter range
 
-Energetically most favorable orientations along $[1 1 0]$ direction ...
 
 \subsection{C$_I$ next to C$_{\text{s}}$}
 
 % c_i and c_s, capaz98, mattoni2002 (restricted to 110 -110 bond chain)
 
 
-\subsection{C$_I$ next to vacancies}
+\subsection{C$_I$ next to V}
 
-\subsection{C$_{\text{s}}$ next to Si self interstitials}
+\subsection{C$_{\text{s}}$ next to Si$_{\text{i}}$}
 
 Non-zeor temperature, entropy, spatial separation of these defects possible, indeed observed in ab initio MD run.