From: hackbard <hackbard@sage.physik.uni-augsburg.de>
Date: Wed, 17 Mar 2010 18:07:24 +0000 (+0100)
Subject: more on vacs
X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=34eafd914200d2dfdceb02cee046d91612011cd1;p=lectures%2Flatex.git

more on vacs
---

diff --git a/posic/thesis/defects.tex b/posic/thesis/defects.tex
index b5d42f5..509c753 100644
--- a/posic/thesis/defects.tex
+++ b/posic/thesis/defects.tex
@@ -968,36 +968,44 @@ On the other hand stretched silicon carbide is obtained by the transition of the
 \begin{figure}[t!h!]
 \begin{center}
 \begin{minipage}[t]{7cm}
-a) \underline{$E_{\text{b}}=-1.53\text{ eV}$}
+a) \underline{Pos: 2, $E_{\text{b}}=-0.59\text{ eV}$}
 \begin{center}
-\includegraphics[width=6.0cm]{00-1dc/1-53.eps}
+\includegraphics[width=6.0cm]{00-1dc/0-59.eps}
 \end{center}
 \end{minipage}
 \begin{minipage}[t]{7cm}
-b) \underline{$E_{\text{b}}=-1.66\text{ eV}$}
+b) \underline{Pos: 3, $E_{\text{b}}=-3.14\text{ eV}$}
 \begin{center}
-\includegraphics[width=6.0cm]{00-1dc/1-66.eps}
+\includegraphics[width=6.0cm]{00-1dc/3-14.eps}
 \end{center}
 \end{minipage}\\[0.2cm]
 \begin{minipage}[t]{7cm}
-c) \underline{$E_{\text{b}}=-1.88\text{ eV}$}
+c) \underline{Pos: 4, $E_{\text{b}}=-0.54\text{ eV}$}
 \begin{center}
-\includegraphics[width=6.0cm]{00-1dc/1-88.eps}
+\includegraphics[width=6.0cm]{00-1dc/0-54.eps}
 \end{center}
 \end{minipage}
 \begin{minipage}[t]{7cm}
-d) \underline{$E_{\text{b}}=-1.38\text{ eV}$}
+d) \underline{Pos: 5, $E_{\text{b}}=-0.50\text{ eV}$}
 \begin{center}
-\includegraphics[width=6.0cm]{00-1dc/1-38.eps}
+\includegraphics[width=6.0cm]{00-1dc/0-50.eps}
 \end{center}
 \end{minipage}
 \end{center}
 \caption{Relaxed structures of defect complexes obtained by creating vacancies at positions 2 (a)), 3 (b)), 4 (c)) and 5 (d)).}
-\label{fig:defects:comb_db_03}
+\label{fig:defects:comb_db_06}
 \end{figure}
-The creation of the vacancy at position 1 ... c interstitital moves to acancy position ending up in a configuration of a substitutional carbon which explains the highbinding energy.
-At position 3 a great amount of strain energy is reduced, since the the vacancy replaces a silicon atom usually bond to and thus starined by the silicon dumbbell atom.
-db moves towards the vacancy in \hkl<1 -1 0> direction.
+Figure \ref{fig:defects:comb_db_06} displays relaxed structures of vacancies in combination with the \hkl<0 0 -1> dumbbell interstital.
+The creation of a vacancy at position 1 results in a configuration of substitutional carbon on a silicon lattice site and no other remaining defects.
+The carbon dumbbell atom moves to position 1 where the vacancy is created and the silicon dumbbell atom recaptures the dumbbell lattice site.
+With a binding energy of -5.39 eV, this is the energetically most favorable configuration observed.
+A great amount of strain energy is reduced by removing the silicon atom at position 3, which is illustrated in figure \ref{fig:defects:comb_db_06} b).
+The dumbbell structure shifts towards the position of the vacancy which replaces the silicon atom usually bond to and at the same time strained by the silicon dumbbell atom.
+Due to the displacement into the \hkl<1 -1 0> direction the bond of the dumbbell silicon atom to the silicon atom on the top left breaks and instead forms a bond to the silicon atom located in \hkl<1 -1 1> direction which is not shown in the figure.
+A binding energy of -3.14 eV is obtained for this structure composing another energetically favorable configuration.
+
+Vacancies created at positions 2 and 4 have similar
+
 Vac at position 2 and 4 have similar results.
 Less strain is reduced, since the displacement of the bottom silicon atom, whcih would be directly bond to the silicon atom replaced by the vacancy, is less.
 In the second case, there is even less strain reduction since the second next neighbour is replaced by the vacancy.
@@ -1012,6 +1020,8 @@ CHECK C-C DIST AND SI-C DIST !!! of all!!!
 {\color{red}Todo: Jahn-Teller distortion (vacancy) $\rightarrow$ actually three possibilities? Due to the initial defect symmetries are broken. It should have relaxed into the minumum energy configuration!?}
 Once a vacancy exists the minimal e conf is the c sub conf and ofcourse necessary for formation of SiC.
 The question is whether the migration into this conf is possible.
+Due to low e of conf at pos 3, this might constitute a trap.
+Thats why we havt to look at migration barriers into the configurations beneficial for SiC prec.
 Fig shows the migration of the 2 and 3 conf into the c sub conf.
 Low migration barriers, which means that SiC will modt probably form ... and so on ...
 
@@ -1024,6 +1034,5 @@ As for the ground state of the single Si self-int a 110 this is also assumed as
 {\color{red}Todo: Model of kick-out and kick-in mechnism?}
 
 
-\section{Summary}
-...
+\section{Conclusions for SiC preciptation}