From ba650d3ea6b60d0872df9873bc7960145bad0b78 Mon Sep 17 00:00:00 2001 From: hackbard Date: Mon, 15 Feb 2010 20:28:10 +0100 Subject: [PATCH] started combo of defects --- posic/thesis/defects.tex | 42 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 39 insertions(+), 3 deletions(-) diff --git a/posic/thesis/defects.tex b/posic/thesis/defects.tex index 2206dee..b421b3d 100644 --- a/posic/thesis/defects.tex +++ b/posic/thesis/defects.tex @@ -568,7 +568,7 @@ Todo: To refine the migration barrier one has to find the saddle point structure \begin{figure}[h] \begin{center} -\includegraphics[width=13cm]{im_00-1_nosym_sp_fullct_thesis.ps}\\[0.5cm] +\includegraphics[width=13cm]{im_00-1_nosym_sp_fullct_thesis.ps}\\[1.5cm] \begin{picture}(0,0)(150,0) \includegraphics[width=2.5cm]{vasp_mig/00-1.eps} \end{picture} @@ -595,7 +595,7 @@ In a second process 0.25 eV of energy are needed for the system to revert into a \begin{figure}[h] \begin{center} -\includegraphics[width=13cm]{vasp_mig/00-1_0-10_nosym_sp_fullct.ps}\\[0.5cm] +\includegraphics[width=13cm]{vasp_mig/00-1_0-10_nosym_sp_fullct.ps}\\[1.6cm] \begin{picture}(0,0)(140,0) \includegraphics[width=2.5cm]{vasp_mig/00-1_a.eps} \end{picture} @@ -620,7 +620,7 @@ The resulting migration barrier of approximately 0.9 eV is very close to the exp \begin{figure}[h] \begin{center} -\includegraphics[width=13cm]{vasp_mig/00-1_ip0-10_nosym_sp_fullct.ps}\\[0.5cm] +\includegraphics[width=13cm]{vasp_mig/00-1_ip0-10_nosym_sp_fullct.ps}\\[1.8cm] \begin{picture}(0,0)(140,0) \includegraphics[width=2.2cm]{vasp_mig/00-1_b.eps} \end{picture} @@ -652,4 +652,40 @@ In addition the bond-ceneterd configuration, for which spin polarized calculatio \section{Combination of point defects} +\begin{figure}[h] +\begin{center} +\begin{minipage}{7.5cm} +\includegraphics[width=7cm]{comb_pos.eps} +\end{minipage} +\begin{minipage}{6.0cm} +\underline{Positions given in $a_{\text{Si}}$}\\[0.3cm] +Initial interstitial: $\frac{1}{4}\hkl<1 1 1>$\\ +Relative silicon neighbour positions: +\begin{enumerate} + \item $\frac{1}{4}\hkl<1 1 -1>$, $\frac{1}{4}\hkl<-1 -1 -1>$ () + \item $\frac{1}{2}\hkl<1 0 1>$, $\frac{1}{2}\hkl<0 1 -1>$,\\[0.2cm] + $\frac{1}{2}\hkl<0 -1 -1>$, $\frac{1}{2}\hkl<-1 0 -1>$ + \item $\frac{1}{4}\hkl<1 -1 1>$, $\frac{1}{4}\hkl<-1 1 1>$ + \item $\frac{1}{4}\hkl<-1 1 -3>$, $\frac{1}{4}\hkl<1 -1 -3>$ + \item $\frac{1}{2}\hkl<-1 -1 0>$, $\frac{1}{2}\hkl<1 1 0>$ +\end{enumerate} +\end{minipage}\\ +\begin{picture}(0,0)(190,20) +\includegraphics[width=2.3cm]{100_arrow.eps} +\end{picture} +\begin{picture}(0,0)(220,0) +\includegraphics[height=2.2cm]{001_arrow.eps} +\end{picture} +\end{center} +\caption[\hkl<0 0 -1> dumbbell interstitial defect and positions of next neighboured silicon atoms used for the second defect.]{\hkl<0 0 -1> dumbbell interstitial defect and positions of next neighboured silicon atoms used for the second defect. Two possibilities exist for red numbered atoms and four possibilities exist for blue numbered atoms.} +\label{fig:defects:pos_of_comb} +\end{figure} +The structural and energetic properties of combinations of point defects are investigated in the following. +The focus is on combinations of the \hkl<0 0 -1> dumbbell interstitial with a second defect. +The second defect is either another \hkl<1 0 0>-type interstitial occupying different orientations, a vacany or a substitutional carbon atom. +Several distances of the two defects are examined. +Investigations are restricted to quantum-mechanical calculations. +Figure \ref{fig:defects:pos_of_comb} shows the initial \hkl<0 0 -1> dumbbell interstitial defect and the positions of the next neighboured silicon atoms used for the second defect. + + -- 2.39.2