From: hackbard Date: Wed, 9 Nov 2011 14:59:32 +0000 (+0100) Subject: istarted sic prec sim results X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=01f5420ca3315280e622d8df277abbd73c4ee4f5;p=lectures%2Flatex.git istarted sic prec sim results --- diff --git a/posic/talks/mpi_app.tex b/posic/talks/mpi_app.tex index 9f6ceb7..358698d 100644 --- a/posic/talks/mpi_app.tex +++ b/posic/talks/mpi_app.tex @@ -1790,14 +1790,10 @@ High probability of stable C$_{\text{sub}}$ configuration \end{center} \end{minipage} }}} - \end{pspicture} \end{slide} -% continue here -\fi - \begin{slide} \headphd @@ -1807,105 +1803,173 @@ High probability of stable C$_{\text{sub}}$ configuration \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) @@ -1924,7 +1988,7 @@ Concerning the precipitation mechanism 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} @@ -1935,51 +1999,76 @@ Concerning the precipitation mechanism }}}} \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 @@ -1999,6 +2088,9 @@ Only short range order observable\\ \end{slide} +\end{document} +\ifnum1=0 + \begin{slide} {\large\bf\boldmath