\end{center}
\end{minipage}
}}}
-
\end{pspicture}
\end{slide}
-% continue here
-\fi
-
\begin{slide}
\headphd
\scriptsize
-\begin{minipage}{6.0cm}
-\includegraphics[width=5.8cm]{c_sub_si110.ps}
-\end{minipage}
-\begin{minipage}{6.3cm}
-\scriptsize
+\vspace{0.3cm}
+
+\begin{minipage}{6.2cm}
+\begin{center}
+{\bf\boldmath C$_{\text{sub}}$ - \si{} \hkl<1 1 0> interaction}
\begin{itemize}
- \item IBS: C may displace Si\\
- $\Rightarrow$ C$_{\text{sub}}$ + \hkl<1 1 0> Si self-interstitial
- \item Assumption:\\
- \hkl<1 1 0>-type $\rightarrow$ favored combination
- \renewcommand\labelitemi{$\Rightarrow$}
- \item Most favorable: \cs{} along \hkl<1 1 0> chain \si{}
- \item Less favorable than C-Si \hkl<1 0 0> dumbbell
+ \item Most favorable: \cs{} along \hkl<1 1 0> chain of \si{}
+ \item Less favorable than ground-state \ci{} \hkl<1 0 0> DB
\item Interaction drops quickly to zero\\
$\rightarrow$ low capture radius
\end{itemize}
-\begin{center}
- {\color{blue}
- IBS process far from equilibrium\\
- \cs{} \& \si{} instead of thermodynamic ground state
- }
\end{center}
\end{minipage}
+\begin{minipage}{0.2cm}
+\hfill
+\end{minipage}
+\begin{minipage}{6.0cm}
+\begin{center}
+{\bf Transition from the ground state}
+\begin{itemize}
+ \item Low transition barrier
+ \item Barrier smaller than \ci{} migration barrier
+ \item Low \si{} migration barrier (\unit[0.67]{eV})\\
+ $\rightarrow$ Separation of \cs{} \& \si{} most probable
+\end{itemize}
+\end{center}
+\end{minipage}\\[0.3cm]
\begin{minipage}{6.0cm}
+\includegraphics[width=6.0cm]{c_sub_si110.ps}
+\end{minipage}
+\begin{minipage}{0.4cm}
+\hfill
+\end{minipage}
+\begin{minipage}{6.0cm}
+\begin{flushright}
\includegraphics[width=6.0cm]{162-097.ps}
+\end{flushright}
\end{minipage}
-\begin{minipage}{6.2cm}
+
+\begin{pspicture}(0,0)(0,0)
+\psline[linewidth=0.05cm,linecolor=gray](6.5,0)(6.5,7.5)
+\rput(6.5,-0.7){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white,linewidth=0.05cm,linecolor=blue]{
+\begin{minipage}{8cm}
\begin{center}
-Ab initio MD at \degc{900}\\
-\includegraphics[width=3.3cm]{md_vasp_01.eps}
-$t=\unit[2230]{fs}$\\
-\includegraphics[width=3.3cm]{md_vasp_02.eps}
-$t=\unit[2900]{fs}$
-\end{center}
-{\color{blue}
-Contribution of entropy to structural formation
+\vspace{0.1cm}
+{\color{black}
+\cs{} \& \si{} instead of thermodynamic ground state\\[0.1cm]
+IBS --- process far from equilibrium\\
}
+\end{center}
\end{minipage}
+}}}
+\end{pspicture}
\end{slide}
-\end{document}
-\ifnum1=0
-
\begin{slide}
- {\large\bf
- Conclusion of defect / migration / combined defect simulations
- }
+\headphd
+{\large\bf
+ Combinations of substitutional C and Si self-interstitials
+}
- \footnotesize
+\scriptsize
-\vspace*{0.1cm}
+\vspace{0.3cm}
-Defect structures
+\begin{minipage}{6.2cm}
+\begin{center}
+{\bf\boldmath C$_{\text{sub}}$ - \si{} \hkl<1 1 0> interaction}
\begin{itemize}
- \item Accurately described by quantum-mechanical simulations
- \item Less accurate description by classical potential simulations
- \item Underestimated formation energy of \cs{} by classical approach
- \item Both methods predict same ground state: \ci{} \hkl<1 0 0> dumbbell
+ \item Most favorable: \cs{} along \hkl<1 1 0> chain of \si{}
+ \item Less favorable than ground-state \ci{} \hkl<1 0 0> DB
+ \item Interaction drops quickly to zero\\
+ $\rightarrow$ low capture radius
\end{itemize}
-
-Migration
-\begin{itemize}
- \item C migration pathway in Si identified
- \item Consistent with reorientation and diffusion experiments
-\end{itemize}
+\end{center}
+\end{minipage}
+\begin{minipage}{0.2cm}
+\hfill
+\end{minipage}
+\begin{minipage}{6.0cm}
+\begin{center}
+{\bf Transition from the ground state}
\begin{itemize}
- \item Different path and ...
- \item overestimated barrier by classical potential calculations
-\end{itemize}
+ \item Low transition barrier
+ \item Barrier smaller than \ci{} migration barrier
+ \item Low \si{} migration barrier (\unit[0.67]{eV})\\
+ $\rightarrow$ Separation of \cs{} \& \si{} most probable
+\end{itemize}
+\end{center}
+\end{minipage}\\[0.3cm]
-Concerning the precipitation mechanism
-\begin{itemize}
- \item Agglomeration of C-Si dumbbells energetically favorable
- (stress compensation)
- \item C-Si indeed favored compared to
- C$_{\text{sub}}$ \& \hkl<1 1 0> Si self-interstitial
- \item Possible low interaction capture radius of
- C$_{\text{sub}}$ \& \hkl<1 1 0> Si self-interstitial
- \item Low barrier for
- \ci{} \hkl<1 0 0> $\rightarrow$ \cs{} \& \si{} \hkl<1 1 0>
- \item In absence of nearby \hkl<1 1 0> Si self-interstitial:
- C-Si \hkl<1 0 0> + Vacancy $\rightarrow$ C$_{\text{sub}}$ (SiC)
-\end{itemize}
+\begin{minipage}{6.0cm}
+\includegraphics[width=6.0cm]{c_sub_si110.ps}
+\end{minipage}
+\begin{minipage}{0.4cm}
+\hfill
+\end{minipage}
+\begin{minipage}{6.0cm}
+\begin{flushright}
+\includegraphics[width=6.0cm]{162-097.ps}
+\end{flushright}
+\end{minipage}
+
+\begin{pspicture}(0,0)(0,0)
+\psline[linewidth=0.05cm,linecolor=gray](6.5,0)(6.5,7.5)
+\rput(6.5,-0.7){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white,linewidth=0.05cm,linecolor=blue]{
+\begin{minipage}{8cm}
+\begin{center}
+\vspace{0.1cm}
+{\color{black}
+\cs{} \& \si{} instead of thermodynamic ground state\\[0.1cm]
+IBS --- process far from equilibrium\\
+}
+\end{center}
+\end{minipage}
+}}}
+\end{pspicture}
+
+% md support
+\begin{pspicture}(0,0)(0,0)
+\rput(6.5,5.0){\psframebox[fillstyle=solid,opacity=0.5,fillcolor=black]{
+\begin{minipage}{14cm}
+\hfill
+\vspace{14cm}
+\end{minipage}
+}}
+\rput(6.5,4.3){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white,linewidth=0.1cm]{
+\begin{minipage}{11cm}
\begin{center}
-{\color{blue}Results suggest increased participation of \cs}
+\vspace{0.2cm}
+\scriptsize
+Ab initio MD at \degc{900}\\[0.4cm]
+\begin{minipage}{5.4cm}
+\centering
+\includegraphics[width=4.3cm]{md01_bonds.eps}\\
+$t=\unit[2230]{fs}$
+\end{minipage}
+\begin{minipage}{5.4cm}
+\centering
+\includegraphics[width=4.3cm]{md02_bonds.eps}\\
+$t=\unit[2900]{fs}$
+\end{minipage}\\[0.5cm]
+{\color{blue}
+Contribution of entropy to structural formation\\[0.1cm]
+}
\end{center}
+\end{minipage}
+}}}
+\end{pspicture}
\end{slide}
\begin{slide}
- {\large\bf
- Silicon carbide precipitation simulations
- }
+\headphd
+{\large\bf
+ Silicon carbide precipitation simulations
+}
- \small
+\small
+
+\vspace{0.2cm}
+
+{\bf Procedure}
{\scriptsize
\begin{pspicture}(0,0)(12,6.5)
Insertion of C atoms at constant T
\begin{itemize}
\item total simulation volume {\pnode{in1}}
- \item volume of minimal SiC precipitate {\pnode{in2}}
+ \item volume of minimal SiC precipitate size {\pnode{in2}}
\item volume consisting of Si atoms to form a minimal {\pnode{in3}}\\
precipitate
\end{itemize}
}}}}
\ncline[]{->}{init}{insert}
\ncline[]{->}{insert}{cool}
- \psframe[fillstyle=solid,fillcolor=white](7.5,0.7)(13.5,6.3)
- \rput(7.8,6){\footnotesize $V_1$}
- \psframe[fillstyle=solid,fillcolor=lightgray](9,2)(12,5)
- \rput(9.2,4.85){\tiny $V_2$}
- \psframe[fillstyle=solid,fillcolor=gray](9.25,2.25)(11.75,4.75)
- \rput(9.55,4.45){\footnotesize $V_3$}
+ \psframe[fillstyle=solid,fillcolor=white](7.3,0.7)(12.8,6.3)
+ \rput(7.6,6){\footnotesize $V_1$}
+ \psframe[fillstyle=solid,fillcolor=lightgray](8.7,2)(11.6,5)
+ \rput(8.9,4.85){\tiny $V_2$}
+ \psframe[fillstyle=solid,fillcolor=gray](8.95,2.25)(11.35,4.75)
+ \rput(9.25,4.45){\footnotesize $V_3$}
\rput(7.9,3.2){\pnode{ins1}}
- \rput(9.22,2.8){\pnode{ins2}}
- \rput(11.0,2.4){\pnode{ins3}}
+ \rput(8.92,2.8){\pnode{ins2}}
+ \rput(10.8,2.4){\pnode{ins3}}
\ncline[]{->}{in1}{ins1}
\ncline[]{->}{in2}{ins2}
\ncline[]{->}{in3}{ins3}
\end{pspicture}
}
+\vspace{-0.5cm}
+
+{\bf Note}
+
+\footnotesize
+
+\begin{minipage}{5.7cm}
\begin{itemize}
- \item Restricted to classical potential simulations
- \item $V_2$ and $V_3$ considered due to low diffusion
- \item Amount of C atoms: 6000
- ($r_{\text{prec}}\approx 3.1\text{ nm}$, IBS: 2 ... 4 nm)
- \item Simulation volume: $31\times 31\times 31$ unit cells
+ \item Amount of C atoms: 6000\\
+ ($r_{\text{prec}}\approx 3.1\text{ nm}$, IBS: \unit[2--4]{nm})
+ \item Simulation volume: $31^3$ Si unit cells\\
(238328 Si atoms)
\end{itemize}
+\end{minipage}
+\begin{minipage}{0.3cm}
+\hfill
+\end{minipage}
+\framebox{
+\begin{minipage}{6.0cm}
+Restricted to classical potential caclulations\\
+$\rightarrow$ Low C diffusion / overestimated barrier\\
+$\rightarrow$ Consider $V_2$ and $V_3$
+%\begin{itemize}
+% \item $V_2$ and $V_3$ considered due to expected low C diffusion
+%\end{itemize}
+\end{minipage}
+}
\end{slide}
+% continue here
+\fi
+
\begin{slide}
- {\large\bf\boldmath
- Silicon carbide precipitation simulations at $450\,^{\circ}\mathrm{C}$ as in IBS
- }
+\headphd
+{\large\bf\boldmath
+ Silicon carbide precipitation simulations at \degc{450} as in IBS
+}
- \small
+\small
-\begin{minipage}{6.5cm}
-\includegraphics[width=6.4cm]{sic_prec_450_si-si_c-c.ps}
+\begin{minipage}{6.2cm}
+\hspace{-0.4cm}\includegraphics[width=6.5cm]{sic_prec_450_si-si_c-c.ps}
+\hfill
\end{minipage}
-\begin{minipage}{6.5cm}
-\includegraphics[width=6.4cm]{sic_prec_450_energy.ps}
+\begin{minipage}{6.2cm}
+\includegraphics[width=6.5cm]{sic_prec_450_energy.ps}
\end{minipage}
-\begin{minipage}{6.5cm}
-\includegraphics[width=6.4cm]{sic_prec_450_si-c.ps}
+\begin{minipage}{6.2cm}
+\hspace{-0.4cm}\includegraphics[width=6.5cm]{sic_prec_450_si-c.ps}
+\hfill
\end{minipage}
-\begin{minipage}{6.5cm}
+\begin{minipage}{6.2cm}
\scriptsize
\underline{Low C concentration ($V_1$)}\\
\hkl<1 0 0> C-Si dumbbell dominated structure
\end{slide}
+\end{document}
+\ifnum1=0
+
\begin{slide}
{\large\bf\boldmath