X-Git-Url: https://hackdaworld.org/gitweb/?a=blobdiff_plain;f=posic%2Ftalks%2Fmpi_app.tex;h=358698d6a10699712337d71d8dff01c5a5c6ba87;hb=01f5420ca3315280e622d8df277abbd73c4ee4f5;hp=2bf8383fd95ba5a487e0f7f27062a15681b7daf9;hpb=1c838933fa76951ad4deb1164e8d2a950b6771cf;p=lectures%2Flatex.git diff --git a/posic/talks/mpi_app.tex b/posic/talks/mpi_app.tex index 2bf8383..358698d 100644 --- a/posic/talks/mpi_app.tex +++ b/posic/talks/mpi_app.tex @@ -1741,218 +1741,235 @@ Interaction along \hkl[1 1 0] \end{slide} -% continue here -\fi - \begin{slide} +\headphd {\large\bf - Defect combinations + Defect combinations of C-Si dimers and vacancies } - \footnotesize -\vspace{0.1cm} +\vspace{0.2cm} -{\bf Combinations of \ci{} \hkl[0 0 -1] and a vacancy}\\ -\begin{minipage}[t]{3cm} -\underline{Pos 2, $E_{\text{b}}=-0.59\text{ eV}$}\\ -\includegraphics[width=2.8cm]{00-1dc/0-59.eps} +\begin{minipage}[b]{2.6cm} +\begin{flushleft} +\underline{V at 2: $E_{\text{b}}=-0.59\text{ eV}$}\\[0.1cm] +\includegraphics[width=2.5cm]{00-1dc/0-59.eps} +\end{flushleft} \end{minipage} - - - -\begin{minipage}[t]{7cm} -\vspace{0.2cm} -\begin{center} - Low activation energies\\ - High activation energies for reverse processes\\ - $\Downarrow$\\ - {\color{blue}C$_{\text{sub}}$ very stable}\\ -\vspace*{0.1cm} - \hrule -\vspace*{0.1cm} - Without nearby \hkl<1 1 0> Si self-interstitial (IBS)\\ - $\Downarrow$\\ - {\color{blue}Formation of SiC by successive substitution by C} -\end{center} +\begin{minipage}[b]{7cm} +\hfill \end{minipage} +\begin{minipage}[b]{2.6cm} +\begin{flushright} +\underline{V at 3, $E_{\text{b}}=-3.14\text{ eV}$}\\[0.1cm] +\includegraphics[width=2.5cm]{00-1dc/3-14.eps} +\end{flushright} +\end{minipage}\\[0.2cm] - -\begin{minipage}[t]{3cm} -\underline{Pos 3, $E_{\text{b}}=-3.14\text{ eV}$}\\ -\includegraphics[width=2.8cm]{00-1dc/3-14.eps} +\begin{minipage}{6.5cm} +\includegraphics[width=6.0cm]{059-539.ps} +\end{minipage} +\begin{minipage}{5.7cm} +\includegraphics[width=6.0cm]{314-539.ps} \end{minipage} +\begin{pspicture}(0,0)(0,0) +\psline[linewidth=0.05cm,linecolor=gray](6.3,9.0)(6.3,0) -\framebox{ -\begin{minipage}{5.9cm} -\includegraphics[width=5.9cm]{vasp_mig/comb_mig_3-2_vac_fullct.ps}\\[0.6cm] +\rput(6.3,7.0){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white,linewidth=0.05cm,linecolor=gray]{ +\begin{minipage}{6.5cm} \begin{center} -\begin{picture}(0,0)(70,0) -\includegraphics[width=1.4cm]{vasp_mig/comb_2-1_init.eps} -\end{picture} -\begin{picture}(0,0)(30,0) -\includegraphics[width=1.4cm]{vasp_mig/comb_2-1_seq_03.eps} -\end{picture} -\begin{picture}(0,0)(-10,0) -\includegraphics[width=1.4cm]{vasp_mig/comb_2-1_seq_06.eps} -\end{picture} -\begin{picture}(0,0)(-48,0) -\includegraphics[width=1.4cm]{vasp_mig/comb_2-1_final.eps} -\end{picture} -\begin{picture}(0,0)(12.5,5) -\includegraphics[width=1cm]{100_arrow.eps} -\end{picture} -\begin{picture}(0,0)(97,-10) -\includegraphics[height=0.9cm]{001_arrow.eps} -\end{picture} -\end{center} -\vspace{0.1cm} -\end{minipage} +IBS: Impinging C creates V \& far away \si\\[0.3cm] +Low migration barrier towards C$_{\text{sub}}$\\ +\&\\ +High barrier for reverse process\\[0.3cm] +{\color{blue} +High probability of stable C$_{\text{sub}}$ configuration } -\begin{minipage}{0.3cm} -\hfill -\end{minipage} -\framebox{ -\begin{minipage}{5.9cm} -\includegraphics[width=5.9cm]{vasp_mig/comb_mig_4-2_vac_fullct.ps}\\[0.1cm] -\begin{center} -\begin{picture}(0,0)(60,0) -\includegraphics[width=0.9cm]{vasp_mig/comb_3-1_init.eps} -\end{picture} -\begin{picture}(0,0)(25,0) -\includegraphics[width=0.9cm]{vasp_mig/comb_3-1_seq_03.eps} -\end{picture} -\begin{picture}(0,0)(-20,0) -\includegraphics[width=0.9cm]{vasp_mig/comb_3-1_seq_07.eps} -\end{picture} -\begin{picture}(0,0)(-55,0) -\includegraphics[width=0.9cm]{vasp_mig/comb_3-1_final.eps} -\end{picture} -\begin{picture}(0,0)(12.5,5) -\includegraphics[width=1cm]{100_arrow.eps} -\end{picture} -\begin{picture}(0,0)(95,0) -\includegraphics[height=0.9cm]{001_arrow.eps} -\end{picture} \end{center} -\vspace{0.1cm} \end{minipage} -} +}}} +\end{pspicture} \end{slide} -\end{document} -\ifnum1=0 - \begin{slide} - {\large\bf\boldmath - Combinations of substitutional C and \hkl<1 1 0> Si self-interstitials - } - - \scriptsize +\headphd +{\large\bf + Combinations of substitutional C and Si self-interstitials +} -\begin{minipage}{6.0cm} -\includegraphics[width=5.8cm]{c_sub_si110.ps} -\end{minipage} -\begin{minipage}{7cm} \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}{6.5cm} -\includegraphics[width=6.0cm]{162-097.ps} +\begin{minipage}{0.2cm} +\hfill +\end{minipage} +\begin{minipage}{6.0cm} +\begin{center} +{\bf Transition from the ground state} \begin{itemize} - \item Low migration barrier + \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}{6.5cm} +\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} -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} \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) @@ -1971,7 +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} @@ -1982,51 +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 @@ -2046,6 +2088,9 @@ Only short range order observable\\ \end{slide} +\end{document} +\ifnum1=0 + \begin{slide} {\large\bf\boldmath