\usepackage{pstricks}
\usepackage{pst-node}
+\usepackage{slashbox}
+
%\usepackage{epic}
%\usepackage{eepic}
fractional & 0.1547 & 0.1676 \\
in \AA & 0.84 & 0.91 \\
\hline
- \end{tabular}
+ \end{tabular}\\[0.2cm]
+ {\scriptsize\underline{PC (Vasp)}}
\includegraphics[width=6.1cm]{c_100_pc_vasp.ps}
\end{center}
\end{minipage}
-
\end{slide}
\begin{slide}
Again: C \hkl<1 0 0> interstitial migration (VASP)
}
- $\hkl<0 0 -1> \rightarrow \hkl<0 0 1>$ migration:
+ $\hkl<0 0 -1> \rightarrow \hkl<0 0 1>$ migration
+ ($3\times 3\times 3$ Type 2):
\small
Again: C \hkl<1 0 0> interstitial migration (VASP)
}
- $\hkl<0 0 -1> \rightarrow \hkl<0 -1 0>$ migration:
+ $\hkl<0 0 -1> \rightarrow \hkl<0 -1 0>$ migration
+ ($3\times 3\times 3$ Type 2):
\small
\Rightarrow \Delta E_{\text{f}} = E_{\text{mig}} = ?.?? \text{ eV}
\]
- Unexpected \& ({\color{red}more} or {\color{orange}less}) fatal:
+ \vspace*{0.5cm}
+ {\large\bf
+ Intermediate configuration {\color{red}not found} by now!
+ }
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ C in Si interstitial configurations (VASP)
+ }
+
+ Check of Kohn-Sham eigenvalues\\
+
+ \small
+
+ \begin{minipage}{6cm}
+ \hkl<1 0 0> interstitial\\
+ \end{minipage}
+ \begin{minipage}{6cm}
+ Saddle point configuration\\
+ \end{minipage}
+ \underline{$4\times 4\times 3$ Type 1 - fixed border atoms}\\
+ \begin{minipage}{6cm}
+385: 4.8567 - 2.00000\\
+386: 4.9510 - 2.00000\\
+387: 5.3437 - 0.00000\\
+388: 5.4930 - 0.00000
+ \end{minipage}
+ \begin{minipage}{6cm}
+385: 4.8694 - 2.00000\\
+386: {\color{red}4.9917} - 1.92603\\
+387: {\color{red}5.1181} - 0.07397\\
+388: 5.4541 - 0.00000
+ \end{minipage}\\[0.2cm]
+ \underline{$4\times 4\times 3$ Type 1 - no constraints}\\
+ \begin{minipage}{6cm}
+385: 4.8586 - 2.00000\\
+386: 4.9458 - 2.00000\\
+387: 5.3358 - 0.00000\\
+388: 5.4915 - 0.00000
+ \end{minipage}
+ \begin{minipage}{6cm}
+385: 4.8693 - 2.00000\\
+386: {\color{red}4.9879} - 1.92065\\
+387: {\color{red}5.1120} - 0.07935\\
+388: 5.4544 - 0.00000
+ \end{minipage}\\[0.2cm]
+ \underline{$3\times 3\times 3$ Type 2 - no constraints}\\
+ \begin{minipage}{6cm}
+433: 4.8054 - 2.00000\\
+434: 4.9027 - 2.00000\\
+435: 5.2543 - 0.00000\\
+436: 5.5718 - 0.00000
+ \end{minipage}
+ \begin{minipage}{6cm}
+433: 4.8160 - 2.00000\\
+434: {\color{green}5.0109} - 1.00264\\
+435: {\color{green}5.0111} - 0.99736\\
+436: 5.5364 - 0.00000
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Once again: C \hkl<1 0 0> interstitial migration (VASP)
+ }
+
+ Method:
\begin{itemize}
- \renewcommand\labelitemi{{\color{orange}$\bullet$}}
- \item Difference in formation energy (0.02 eV)
- of the initial and final configuration
- \renewcommand\labelitemi{{\color{red}$\bullet$}}
- \item Huge discrepancy (0.3 - 0.4 eV) to the migration barrier
- of Type 1 (198+1 atoms) calculations
- \renewcommand\labelitemi{{\color{black}$\bullet$}}
+ \item Start in fully relaxed (assumed) saddle point configuration
+ \item Move towards \hkl<1 0 0> configuration using updated values
+ for $\Delta x$, $\Delta y$ and $\Delta z$ (CRT)
+ \item \hkl<1 1 0> constraints applied, 1 Si atom fixed
+ \item $4\times 4\times 3$ Type 1 supercell
+ \end{itemize}
+
+ Results:
+
+ \begin{minipage}{6.2cm}
+ \includegraphics[width=6.0cm]{c_100_110sp-i_vasp.ps}
+ \end{minipage}
+ \begin{minipage}{6.2cm}
+ \includegraphics[width=6.0cm]{c_100_110sp-i_rc_vasp.ps}
+ \end{minipage}
+
+ Reaction coordinate:
+ $r_{i+1}=r_i+\sum_{\text{atoms j}} \left| r_{j,i+1}-r_{j,i} \right|$
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Investigation of the migration path along \hkl<1 1 0> (VASP)
+ }
+
+ \small
+
+ \underline{Minimum:}\\
+ \begin{minipage}{4cm}
+ \includegraphics[width=3.5cm]{c_100_mig_vasp/110_c-si_split.eps}
+ \end{minipage}
+ \begin{minipage}{8cm}
+ \begin{itemize}
+ \item Starting conf: 35 \% displacement results (1443)
+ \item \hkl<1 1 0> constraint disabled
+ \end{itemize}
+ \begin{center}
+ $\Downarrow$
+ \end{center}
+ \begin{itemize}
+ \item C-Si \hkl<1 1 0> split interstitial
+ \item Stable configuration
+ \item $E_{\text{f}}=4.13\text{ eV}$
+ \end{itemize}
+ \end{minipage}\\[0.1cm]
+
+ \underline{Maximum:}\\
+ \begin{minipage}{6cm}
+ \begin{center}
+ \includegraphics[width=2.3cm]{c_100_mig_vasp/100-110_01.eps}
+ \includegraphics[width=2.3cm]{c_100_mig_vasp/100-110_02.eps}\\
+ 20 \% $\rightarrow$ 25 \%\\
+ Breaking of Si-C bond
+ \end{center}
+ \end{minipage}
+ \begin{minipage}{6cm}
+ \includegraphics[width=6.2cm]{c_100_110sp-i_upd_vasp.ps}
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Displacing the \hkl<1 1 0> Si-C split along \hkl<1 -1 0> (VASP)
+ }
+
+ \small
+
+ $4\times 4\times 3$ Type 1 supercell
+
+ \underline{Structures:}
+
+ \begin{minipage}[t]{4.1cm}
+ \includegraphics[height=3.0cm]{c_100_mig_vasp/start.eps}\\
+ \hkl<0 0 -1> dumbbell\\
+ $E_{\text{f}}={\color{orange}3.2254}\text{ eV}$
+ \end{minipage}
+ \begin{minipage}[t]{4.1cm}
+ \includegraphics[height=3.0cm]{c_100_mig_vasp/110_c-si_split.eps}\\
+ Assumed \hkl<1 1 0> C-Si split\\
+ $E_{\text{f}}=4.1314\text{ eV}$
+ \end{minipage}
+ \begin{minipage}[t]{4.1cm}
+ \includegraphics[height=3.0cm]{c_100_mig_vasp/110_dis_0-10.eps}\\
+ First guess: \hkl<0 -1 0> dumbbell\\
+ {\color{red}but:} $E_{\text{f}}={\color{orange}2.8924}\text{ eV}$\\
+ Third bond missing!
+ \end{minipage}\\
+
+ \underline{Occupancies:}
+
+ \scriptsize
+
+ \begin{minipage}{4.1cm}
+385: 4.8586 - 2.00000\\
+386: 4.9458 - 2.00000\\
+387: 5.3358 - 0.00000\\
+388: 5.4915 - 0.00000
+\hfill
+ \end{minipage}
+ \begin{minipage}{4.1cm}
+385: 4.7790 - 2.00000\\
+386: 4.8797 - 1.99964\\
+387: 5.1321 - 0.00036\\
+388: 5.4711 - 0.00000
+\hfill
+ \end{minipage}
+ \begin{minipage}{4.1cm}
+385: 4.7670 - 2.00000\\
+386: 4.9190 - 2.00000\\
+387: 5.2886 - 0.00000\\
+388: 5.4849 - 0.00000
+\hfill
+ \end{minipage}\\
+
+\small
+
+ \begin{center}
+ {\color{red}? ! ? ! ? ! ? ! ?}
+ \end{center}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ C \hkl<1 0 0> interstitial migration (VASP)
+ }
+
+ \small
+
+ \begin{minipage}{6.2cm}
+ \begin{itemize}
+ \item $3\times 3\times 3$ Type 2 supercell
+ \item \hkl<1 1 0> constraints applied
+ (\href{http://www.physik.uni-augsburg.de/~zirkelfr/download/posic/sd_rot.patch}{Patch})
+ \item Move from \hkl<1 0 0> towards\\
+ bond centered configuration
+ \end{itemize}
+ \underline{Sd Rot usage (POSCAR):}
+\begin{verbatim}
+cubic diamond
+5.480
+ 3.0 0.0 0.0
+ 0.0 3.0 0.0
+ 0.0 0.0 3.0
+216 1
+Transformed selective dynamics
+45.0 0.0
+Direct
+ ...
+\end{verbatim}
+Only works in direct mode!\\
+$z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
+ \end{minipage}
+ \begin{minipage}{6.2cm}
+ \includegraphics[width=5cm]{c_100_110sp-i_2333_vasp.ps}
+ \includegraphics[width=5cm]{c_100_110sp-i_2333_rc_vasp.ps}\\
+ {\color{red}One fixed Si atom not enough!}\\
+ Video: \href{../video/c_in_si_233_110mig_vasp.avi}{$\rhd_{\text{local}}$ } $|$
+ \href{http://www.physik.uni-augsburg.de/~zirkelfr/download/posic/c_in_si_233_110mig_vasp.avi}{$\rhd_{\text{remote url}}$}\\
+ \end{minipage}
+
+ {\color{blue}
+ Next: Migration calculation in 2333 using CRT
+ (\hkl<0 0 -1> $\rightarrow$ \hkl<0 0 1> and \hkl<0 -1 0>)
+ }
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Defect configurations in $4\times 4\times 3$ Type 1 supercells revisited
+ }
+
+ \footnotesize
+
+ \begin{tabular}{l|p{2.5cm}|p{2.5cm}|p{4cm}|}
+ & \hkl<0 0 -1> interstitial
+ & local minimum\newline
+ \hkl<1 1 0> C-Si split
+ & intermediate configuration\newline
+ (bond centered conf)\\
+ \hline
+ default & $E_{\text{f}}=3.3254\text{ eV}$\newline
+ {\tiny
+ 386: 4.9458 - 2.00000\newline
+ 387: 5.3358 - 0.00000}
+ & $E_{\text{f}}=4.1314\text{ eV}$\newline
+ {\tiny
+ 386: 4.8797 - 1.99964\newline
+ 387: 5.1321 - 0.00036}
+ & $E_{\text{f}}=4.2434\text{ eV}$\newline
+ {\tiny
+ 386: 4.9879 - 1.92065\newline
+ 387: 5.1120 - 0.07935} \\
+ \hline
+ No symmetry & $E_{\text{f}}=3.3154\text{ eV}$\newline
+ {\tiny
+ 386: 4.9456 - 2.00000\newline
+ 387: 5.3366 - 0.00000}
+ & $E_{\text{f}}=4.1314\text{ eV}$\newline
+ {\tiny
+ 386: 4.8798 - 1.99961\newline
+ 387: 5.1307 - 0.00039}
+ & $E_{\text{f}}=4.2454\text{ eV}$\newline
+ {\tiny
+ 386: 4.9841 - 1.92147\newline
+ 387: 5.1085 - 0.07853} \\
+ \hline
+ $+$ spin polarized & $E_{\text{f}}=3.3154\text{ eV}$\newline
+ {\tiny
+ {\color{blue}
+ 386: 4.9449 - 1.00000\newline
+ 387: 5.3365 - 0.00000\newline%
+ }%
+ {\color{green}%
+ 386: 4.9449 - 1.00000\newline
+ 387: 5.3365 - 0.00000}}
+ & $E_{\text{f}}={\color{red}4.1314}\text{ eV}$\newline
+ {\tiny
+ {\color{blue}
+ 386: 4.8799 - 0.99980\newline
+ 387: 5.1307 - 0.00020\newline%
+ }%
+ {\color{green}%
+ 386: 4.8799 - 0.99980\newline
+ 387: 5.1306 - 0.00020}}
+ & $E_{\text{f}}=4.0254\text{ eV}$\newline
+ {\tiny
+ {\color{blue}
+ 387: 4.8581 - 1.00000\newline
+ 388: 5.4662 - 0.00000\newline%
+ }%
+ {\color{green}%
+ 385: 4.8620 - 1.00000\newline
+ 386: 5.2951 - 0.00000}} \\
+ \hline
+ $+$ spin difference 2 & $E_{\text{f}}=3.6394\text{ eV}$\newline
+ {\tiny
+ {\color{blue}
+ 387: 5.2704 - 0.99891\newline
+ 388: 5.4886 - 0.00095\newline
+ 389: 5.5094 - 0.00011\newline
+ 390: 5.5206 - 0.00003\newline%
+ }%
+ {\color{green}%
+ 385: 4.8565 - 0.98603\newline
+ 386: 5.0119 - 0.01397}}
+ & Relaxation into\newline
+ bond centered\newline
+ configuration\newline
+ $\rightarrow$
+ & $E_{\text{f}}=4.0254\text{ eV}$\newline
+ {\tiny
+ {\color{blue}
+ 387: 4.8578 - 1.00000\newline
+ 388: 5.4661 - 0.00000\newline%
+ }%
+ {\color{green}%
+ 385: 4.8618 - 1.00000\newline
+ 386: 5.2950 - 0.00000}} \\
+ \hline
+ \end{tabular}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Defect configurations in $3\times 3\times 3$ Type 2 supercells revisited\\
+ }
+
+ \footnotesize
+
+ \begin{tabular}{l|p{2.5cm}|p{2.5cm}|p{4cm}|}
+ & \hkl<0 0 -1> interstitial
+ & local minimum\newline
+ \hkl<1 1 0> C-Si split
+ & intermediate configuration\newline
+ (bond centered conf)\\
+ \hline
+ default & $E_{\text{f}}=3.15407\text{ eV}$\newline
+ {\tiny
+ 434: 4.9027 - 2.00000\newline
+ 435: 5.2543 - 0.00000}
+ & $E_{\text{f}}=??\text{ eV}$\newline
+ {\tiny
+ ??\newline
+ ??}
+ & $E_{\text{f}}=4.40907\text{ eV}$\newline
+ {\tiny
+ 434: 5.0109 - 1.00264\newline
+ 435: 5.0111 - 0.99736}\\
+ \hline
+ No symmetry & $E_{\text{f}}=3.16107\text{ eV}$\newline
+ {\tiny
+ 434: 4.9032 - 2.00000\newline
+ 435: 5.2547 - 0.00000}
+ & $E_{\text{f}}=??\text{ eV}$\newline
+ {\tiny
+ ??\newline
+ ??}
+ & $E_{\text{f}}=4.41507\text{ eV}$\newline
+ {\tiny
+ 434: 5.0113 - 1.00140\newline
+ 435: 5.0114 - 0.99860} \\
+ \hline
+ $+$ spin polarized & $E_{\text{f}}=3.16107\text{ eV}$\newline
+ {\tiny
+ {\color{blue}
+ 434: 4.9033 - 1.00000\newline
+ 435: 5.2544 - 0.00000\newline%
+ }%
+ {\color{green}%
+ 434: 4.9035 - 1.00000\newline
+ 435: 5.2550 - 0.00000}}
+ & $E_{\text{f}}=??\text{ eV}$\newline
+ {\tiny
+ {\color{blue}
+ ??\newline
+ ??\newline%
+ }%
+ {\color{green}%
+ ??\newline
+ ??}}
+ & $E_{\text{f}}=4.10307\text{ eV}$\newline
+ {\tiny
+ {\color{blue}
+ 435: 4.8118 - 1.00000\newline
+ 436: 5.5360 - 0.00000\newline%
+ }%
+ {\color{green}%
+ 433: 4.8151 - 1.00000\newline
+ 434: 5.3475 - 0.00000}} \\
+ \hline
+ \end{tabular}
+
+ \normalsize
+
+ \vspace*{0.3cm}
+
+ {\color{blue}Tracer:}\\
+ Smearing of electrons over two or more (degenerated) energy levels\\
+ $\Rightarrow$ use spin polarized calculations!
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Bond centered configuration revisited ($3\times 3\times 3$ Type 2)
+ }
+
+ Spin polarized calculations
+
+ {\small
+ \begin{minipage}[t]{5.8cm}
+ \underline{Kohn-Sham eigenvalues}\\
+ \begin{minipage}{2.8cm}
+ Spin up:\\
+ 430: 4.2639 - 1\newline
+ 431: 4.7332 - 1\newline
+ 432: 4.7354 - 1\newline
+ 433: 4.7700 - 1\newline
+ 434: 4.8116 - 1\newline
+ 435: 4.8118 - 1\newline
+ 436: 5.5360 - 0\newline
+ 437: 5.5623 - 0
+ \end{minipage}
+ \begin{minipage}{2.8cm}
+ Spin down:\\
+ 430: 4.2682 - 1\newline
+ 431: 4.7738 - 1\newline
+ 432: 4.8150 - 1\newline
+ 433: 4.8151 - 1\newline
+ 434: 5.3475 - 0\newline
+ 435: 5.3476 - 0\newline
+ 436: 5.5455 - 0\newline
+ 437: 5.5652 - 0
+ \end{minipage}\\[0.3cm]
+ \begin{itemize}
+ \item linear Si-C-Si bond
+ \item Each Si has another 3 Si neighbours
+ \end{itemize}
+ \begin{center}
+ {\color{blue}Spin polarized calculations necessary!}\\[0.3cm]
+ \end{center}
+ {\scriptsize Charge density isosurface of
+ {\color{gray}spin up}, {\color{green}spin down} and
+ the {\color{blue}resulting spin up} electrons.\\
+ Two {\color{yellow} Si} atoms and one {\color{red}C}
+ atom are shown.
+ }
+ \end{minipage}
+ \begin{minipage}[t]{6.5cm}
+ \underline{MO diagram}\\
+ \begin{minipage}[t]{1.2cm}
+ {\color{red}Si}\\
+ {\tiny sp$^3$}\\[0.8cm]
+ \underline{${\color{red}\uparrow}$}
+ \underline{${\color{red}\uparrow}$}
+ \underline{${\color{red}\uparrow}$}
+ \underline{${\color{red}\uparrow}$}\\
+ sp$^3$
+ \end{minipage}
+ \begin{minipage}[t]{1.4cm}
+ \begin{center}
+ {\color{red}M}{\color{blue}O}\\[1.0cm]
+ \underline{${\color{blue}\uparrow}{\color{white}\downarrow}$}\\
+ $\sigma_{\text{ab}}$\\[0.5cm]
+ \underline{${\color{red}\uparrow}{\color{blue}\downarrow}$}\\
+ $\sigma_{\text{b}}$
+ \end{center}
+ \end{minipage}
+ \begin{minipage}[t]{1.0cm}
+ \begin{center}
+ {\color{blue}C}\\
+ {\tiny sp}\\[0.2cm]
+ \underline{${\color{white}\uparrow\uparrow}$}
+ \underline{${\color{white}\uparrow\uparrow}$}\\
+ 2p\\[0.4cm]
+ \underline{${\color{blue}\uparrow}{\color{blue}\downarrow}$}
+ \underline{${\color{blue}\uparrow}{\color{blue}\downarrow}$}\\
+ sp
+ \end{center}
+ \end{minipage}
+ \begin{minipage}[t]{1.4cm}
+ \begin{center}
+ {\color{blue}M}{\color{green}O}\\[1.0cm]
+ \underline{${\color{blue}\uparrow}{\color{white}\downarrow}$}\\
+ $\sigma_{\text{ab}}$\\[0.5cm]
+ \underline{${\color{green}\uparrow}{\color{blue}\downarrow}$}\\
+ $\sigma_{\text{b}}$
+ \end{center}
+ \end{minipage}
+ \begin{minipage}[t]{1.2cm}
+ \begin{flushright}
+ {\color{green}Si}\\
+ {\tiny sp$^3$}\\[0.8cm]
+ \underline{${\color{green}\uparrow}$}
+ \underline{${\color{green}\uparrow}$}
+ \underline{${\color{green}\uparrow}$}
+ \underline{${\color{green}\uparrow}$}\\
+ sp$^3$
+ \end{flushright}
+ \end{minipage}\\[0.4cm]
+ \begin{flushright}
+ \includegraphics[width=6cm]{c_100_mig_vasp/im_spin_diff.eps}
+ \end{flushright}
+ \end{minipage}
+ }
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ \hkl<0 0 -1> configuration revisited ($3\times 3\times 3$ Type 2)
+ }
+
+ Spin polarized calculations
+
+ {\small
+ \begin{minipage}[t]{5.8cm}
+ \underline{Kohn-Sham eigenvalues}\\
+ \begin{minipage}{2.8cm}
+ Spin up:\\
+ 430: 4.3317 - 1\newline
+ 431: 4.7418 - 1\newline
+ 432: 4.8014 - 1\newline
+ 433: 4.8060 - 1\newline
+ 434: 4.9033 - 1\newline
+ 435: 5.2544 - 0\newline
+ 436: 5.5723 - 0\newline
+ 437: 5.5848 - 0
+ \end{minipage}
+ \begin{minipage}{2.8cm}
+ Spin down:\\
+ 430: 4.3317 - 1\newline
+ 431: 4.7420 - 1\newline
+ 432: 4.8013 - 1\newline
+ 433: 4.8059 - 1\newline
+ 434: 4.9035 - 1\newline
+ 435: 5.2550 - 0\newline
+ 436: 5.5724 - 0\newline
+ 437: 5.5846 - 0
+ \end{minipage}
+ \end{minipage}
+ \begin{minipage}[t]{6.5cm}
+ \underline{MO diagram}\\
+ \begin{minipage}[t]{1.2cm}
+ {\color{red}Si}\\
+ {\tiny sp$^2$}\\[0.1cm]
+ \underline{${\color{white}\uparrow}$}\\
+ p\\[0.4cm]
+ \underline{${\color{red}\uparrow\downarrow}$}
+ \underline{${\color{red}\uparrow}{\color{white}\downarrow}$}
+ \underline{${\color{red}\uparrow}{\color{white}\downarrow}$}\\
+ sp$^2$
+ \end{minipage}
+ \begin{minipage}[t]{1.2cm}
+ \begin{flushright}
+ {\color{red}M}\\[1.0cm]
+ \underline{${\color{white}\uparrow}{\color{white}\downarrow}$}\\
+ $\sigma_{\text{ab}}$\\[0.5cm]
+ \underline{${\color{red}\uparrow}{\color{blue}\downarrow}$}\\
+ $\sigma_{\text{b}}$
+ \end{flushright}
+ \end{minipage}
+ \begin{minipage}[t]{1.2cm}
+ \begin{flushleft}
+ {\color{blue}O}\\[0.4cm]
+ \underline{${\color{white}\uparrow}{\color{white}\downarrow}$}\\
+ $\pi_{\text{ab}}$\\[0.5cm]
+ \underline{${\color{red}\uparrow}{\color{blue}\downarrow}$}\\
+ $\pi_{\text{b}}$
+ \end{flushleft}
+ \end{minipage}
+ \begin{minipage}[t]{2.0cm}
+ \begin{center}
+ {\color{blue}C}\\
+ {\tiny sp$^2$}\\[0.5cm]
+ \underline{${\color{white}\uparrow\uparrow}$}\\
+ p\\[0.4cm]
+ \underline{${\color{blue}\uparrow}{\color{blue}\downarrow}$}
+ \underline{${\color{blue}\uparrow}{\color{white}\downarrow}$}
+ \underline{${\color{blue}\uparrow}{\color{white}\downarrow}$}\\
+ sp$^2$
+ \end{center}
+ \end{minipage}
+ \end{minipage}
+ }
+
+ \vspace*{0.4cm}
+
+ \begin{itemize}
+ \item Si-C double bond
+ \item Si and C atom have another 2 Si neighbours
+ \end{itemize}
+
+ \begin{center}
+ {\color{blue}Spin polarized calculations {\color{red}not} necessary!}
+ \end{center}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Kohn-Sham levels visualized
+ }
+
+ \begin{minipage}{6cm}
+ \underline{\hkl<0 0 -1> configuration}
+ \begin{center}
+ \includegraphics[height=8cm]{c_100_mig_vasp/100_ksl.ps}
+ \end{center}
+ \end{minipage}
+ \begin{minipage}{6cm}
+ \underline{Saddle point configuration}
+ \begin{center}
+ \includegraphics[height=8cm]{c_100_mig_vasp/im_ksl.ps}
+ \end{center}
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ New default parameter set\\[1cm]
+ }
+
+ Since some defect configurations need spin polarized calculations ...\\[1cm]
+
+ from now on the default parameter set\\
+ {\bf\color{blue}
+ $+$ no symmetry\\
+ $+$ spin polarized\\
+ }
+ \ldots is used!\\[1cm]
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ \hkl<0 0 -1> to \hkl<0 0 1> migration
+ in the $3\times 3\times 3$ Type 2 supercell
+ }
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ \hkl<0 0 -1> to \hkl<0 -1 0> migration
+ in the $3\times 3\times 3$ Type 2 supercell
+ }
+
+ \includegraphics[width=6cm]{c_00-1_0-10_mig_vasp.ps}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Combination of defects
+ }
+
+ TODO: introduce some Si self-interstitials and C interstitials before\\
+ BUT: Concentrate on 100 C interstitial combinations and 100 C + vacancy\\
+
+ Agglomeration of 100 defects energetically favorable?
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Silicon point defects
+ }
+
+ \begin{minipage}{3.2cm}
+ \underline{Vacancy}
+ \begin{itemize}
+ \item $E_{\text{f}}=3.63\text{ eV}$
+ \end{itemize}
+ \includegraphics[width=3cm]{si_pd_vasp/vac_2333.eps}\\
+ \underline{\hkl<1 1 0> interstitial}
+ \begin{itemize}
+ \item $E_{\text{f}}=3.39\text{ eV}$
+ \end{itemize}
+ \includegraphics[width=3cm]{si_pd_vasp/110_2333.eps}
+ \end{minipage}
+ \begin{minipage}{4.5cm}
+ \begin{center}
+ \includegraphics[height=8cm]{si_pd_vasp/vac_2333_ksl.ps}\\
+ {\scriptsize Vacancy}
+ \end{center}
+ \end{minipage}
+ \begin{minipage}{4.5cm}
+ \begin{center}
+ \includegraphics[height=8cm]{si_pd_vasp/110_2333_ksl.ps}
+ {\scriptsize \hkl<1 1 0> interstitial}
+ \end{center}
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Silicon point defects
+ }
+
+ \begin{minipage}{3.1cm}
+ \underline{Hexagonal}
+ \begin{itemize}
+ \item $E_{\text{f}}=3.42\text{ eV}$
+ \end{itemize}
+ \includegraphics[width=3cm]{si_pd_vasp/hex_2333.eps}\\
+ \underline{Tetrahedral}
+ \begin{itemize}
+ \item $E_{\text{f}}=3.77\text{ eV}$
+ \end{itemize}
+ \includegraphics[width=3cm]{si_pd_vasp/tet_2333.eps}
+ \end{minipage}
+ \begin{minipage}{3.7cm}
+ \begin{center}
+ \includegraphics[height=8cm]{si_pd_vasp/hex_2333_ksl.ps}\\
+ {\scriptsize Hexagonal}
+ \end{center}
+ \end{minipage}
+ \begin{minipage}{3.7cm}
+ \begin{center}
+ \includegraphics[height=8cm]{si_pd_vasp/tet_2333_ksl.ps}
+ {\scriptsize Tetrahedral}
+ \end{center}
+ \end{minipage}
+ \begin{minipage}[c]{0.1cm}
+ \hfill
+ \end{minipage}
+ \begin{minipage}[c]{1.9cm}
+{\tiny
+\underline{Energy - Occup.}\\
+5.5063 - 0.32840\\
+5.5064 - 0.32793\\
+5.5064 - 0.32764\\
+5.5777 - 0.00691\\
+5.5777 - 0.00691\\
+5.6031 - 0.00074\\
+5.6031 - 0.00074\\
+5.6035 - 0.00071\\
+5.6357 - 0.00002\\
+5.6453 - 0.00001\\
+5.6453 - 0.00001
+}
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Carbon point defects in silicon
+ }
+
+ \begin{minipage}{3.2cm}
+ \underline{C substitutional}
+ \begin{itemize}
+ \item $E_{\text{f}}=1.39\text{ eV}$
\end{itemize}
+ \includegraphics[width=3cm]{c_pd_vasp/sub_2333.eps}\\
+ \underline{\hkl<1 0 0> interstitial}
+ \begin{itemize}
+ \item $E_{\text{f}}=3.15\text{ eV}$
+ \end{itemize}
+ \includegraphics[width=3cm]{c_pd_vasp/100_2333.eps}
+ \end{minipage}
+ \begin{minipage}{4.5cm}
+ \begin{center}
+ \includegraphics[height=8cm]{c_pd_vasp/sub_2333_ksl.ps}\\
+ {\scriptsize C substitutional}
+ \end{center}
+ \end{minipage}
+ \begin{minipage}{4.5cm}
+ \begin{center}
+ \includegraphics[height=8cm]{c_pd_vasp/100_2333_ksl.ps}
+ {\scriptsize \hkl<1 0 0> interstitial}
+ \end{center}
+ \end{minipage}
\end{slide}
+\begin{slide}
+
+ {\large\bf\boldmath
+ Combination of defects
+ }
+
+ \begin{itemize}
+ \item Supercell: $3\times 3\times 3$ Type 2
+ \item Starting configuration: \hkl<0 0 -1> C-Si interstitial
+ \item Energies: $E_{\text{f}}$ of the interstitial combinations in eV
+ \end{itemize}
+
+ \underline{Along \hkl<1 1 0>:}
+
+ \begin{tabular}{|l|p{1.8cm}|p{1.8cm}|p{1.8cm}|p{1.8cm}|}
+ \hline
+ {\scriptsize
+ \backslashbox{2nd interstitial}{Distance $[\frac{a}{4}]$}
+ }
+ & \hkl<1 1 -1> & \hkl<2 2 0> & \hkl<3 3 -1> & \hkl<4 4 0>\\
+ \hline
+ \hkl<0 0 -1> & 6.23\newline {\color{blue}6.23514}
+ & 4.65\newline {\color{blue}4.65014}
+ & 5.97\newline {\color{blue}5.97314}
+ & 6.45\newline {\color{blue}6.45714} \\
+ \hline
+ \hkl<0 0 1> & 6.64\newline {\color{blue}6.65114}
+ & 4.78\newline {\color{blue}4.78314}
+ & 6.53\newline {\color{blue}6.53614}
+ & 6.18\newline {\color{blue}6.18914} \\
+ \hline
+ \hkl<1 0 0>, \hkl<0 1 0> & 4.06\newline alkmene
+ & 4.93
+ & 5.72
+ & 6.00\\
+ \hline
+ \hkl<-1 0 0>, \hkl<0 -1 0> & 3.92 & 4.43 & 6.02 & 6.02 \\
+ \hline
+ Vacancy & ... & ... & ... & ... \\
+ \hline
+ \end{tabular}
+
+ Spin polarized and {\color{blue}non spin polarized} results
+
+\end{slide}
+
+\begin{slide}
+
+ \begin{minipage}{5cm}
+ {\large\bf\boldmath
+ Combination of defects
+ }
+
+ \scriptsize
+
+ Initial insterstital at: $\frac{1}{4}\hkl<1 1 1>$
+
+ Relative silicon neighbour positions:
+ \begin{enumerate}
+ \item The dumbbell Si
+ \item $\frac{1}{4}\hkl<1 1 -1>$, $\frac{1}{4}\hkl<-1 -1 -1>$
+ \item $\frac{1}{2}\hkl<1 0 -1>$, $\frac{1}{2}\hkl<0 1 -1>$,
+ $\frac{1}{2}\hkl<0 -1 -1>$, $\frac{1}{2}\hkl<-1 0 -1>$
+ \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 $\frac{1}{2}\hkl<-1 -1 0>$, $\frac{1}{2}\hkl<1 1 0>$
+ \item $\frac{1}{2}\hkl<1 -1 0>$, $\frac{1}{2}\hkl<-1 1 0>$
+ \item $\frac{1}{4}\hkl<-1 3 -1>$, $\frac{1}{4}\hkl<1 -3 -1>$,
+ $\frac{1}{4}\hkl<3 -1 -1>$. $\frac{1}{4}\hkl<-3 1 -1>$
+ \item $\hkl<0 0 -1>$
+ \item $\frac{1}{2}\hkl<1 0 1>$, $\frac{1}{2}\hkl<0 1 1>$,
+ $\frac{1}{2}\hkl<0 -1 1>$, $\frac{1}{2}\hkl<-1 0 1>$
+ \item $\frac{1}{4}\hkl<-1 -3 1>$, $\frac{1}{4}\hkl<-3 -1 1>$,
+ $\frac{1}{4}\hkl<1 3 1>$, $\frac{1}{4}\hkl<3 1 1>$
+ \item $\frac{1}{4}\hkl<1 3 -3>$, $\frac{1}{4}\hkl<3 1 -3>$,
+ $\frac{1}{4}\hkl<-1 -3 -3>$, $\frac{1}{4}\hkl<-3 -1 -3>$
+ \item $\hkl<1 0 0>$, $\hkl<0 1 0>$, $\hkl<-1 0 0>$, $\hkl<0 -1 0>$
+ \item $\frac{1}{4}\hkl<1 1 3>$, $\frac{1}{4}\hkl<-1 -1 3>$
+ \item $\frac{1}{4}\hkl<3 3 -1>$, $\frac{1}{4}\hkl<-3 -3 -1>$
+ \item $\frac{1}{2}\hkl<1 1 -2>$, $\frac{1}{2}\hkl<-1 -1 -2>$,
+ \item $\frac{1}{2}\hkl<1 -1 -2>$, $\frac{1}{2}\hkl<-1 1 -2>$
+ \end{enumerate}
+ One of a kind\\
+ {\color{red}Two of a kind}\\
+ {\color{blue}Four of a kind}
+ \end{minipage}
+ \begin{minipage}{6cm}
+ \includegraphics[width=8cm]{c_100_next_neighbours_02.eps}
+ \begin{center}
+ \includegraphics[width=5cm]{c_100_res_bonds_vasp.ps}
+ \end{center}
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+ Combination of defects
+ }
+
+ \begin{tabular}{|l|l|l|l|l|l|}
+ \hline
+ & 2 & 3 & 4 & 5 & 6 \\
+ \hline
+\hkl<0 0 -1> & 6.23 & 5.16 & 6.23 & ... & 4.65\\
+ \hline
+\hkl<0 0 1> & 6.64 & 6.31 & ... & ... & 4.78 \\
+ \hline
+\hkl<1 0 0> & 4.06 & 6.13 & 6.21 & ... & 4.93 \\
+ \hline
+\hkl<-1 0 0> & \hkl<0 -1 0> & 4.41 & ... & ... & 4.43 \\
+ \hline
+\hkl<0 1 0> & \hkl<1 0 0> & 5.95 & \hkl<-1 0 0> & \hkl<-1 0 0> & \hkl<1 0 0> \\
+ \hline
+\hkl<0 -1 0> & 3.92 & ... & \hkl<1 0 0> & \hkl<1 0 0> & \hkl <-1 0 0> \\
+ \hline
+Vacancy & ... & ... & ... & ... & ... \\
+ \hline
+ \end{tabular}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Brainstorming: Point defects in Si (as grown and as implanted)
+ }
+
+ \small
+
+ Supercell size: $2$ - $2000 \cdot 10^{-21}\text{ cm}^3$
+
+ \underline{After crystal growth}
+ \begin{itemize}
+ \item Si point defects at $450\, ^{\circ}\text{C}$
+ \begin{itemize}
+ \item Interstitials:
+ \item Vacancies:
+ \end{itemize}
+ \item C impurities: $10^{17}\text{ cm}^{-3}$\\
+ $\Rightarrow$ $10^{-4}$ -- $10^{-1}$ per sc
+ $\rightarrow$ neglected in simulations
+ \end{itemize}
+
+ \underline{After/during implantation}
+ \begin{itemize}
+ \item Si point defects\\
+ $E_{\text{d}}^{\text{av}}=35\text{ eV}$,
+ $D_{\text{imp}}=1\text{ -- }4 \cdot 10^{17}\text{ cm }^{-2}$,
+ $d_{\text{sc}}=3\text{ -- }30\cdot 4.38\text { \AA}$,
+ $A=(3\text{ -- }30\text{ \AA})^2$,\\
+ Amount of collisions with $\Delta E > E_{\text{d}}$
+ in depth region $[h,h+d_{\text{sc}}]$: $n=$ .. (SRIM)\\
+ $\Rightarrow N_{\text{FP}}=nAD$
+ \item C point defects
+ \begin{itemize}
+ \item Substitutional C: ...
+ \item Intesrtitial C: ...
+ \end{itemize}
+ \end{itemize}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Reminder (just for me to keep in mind ...)
+ }
+
+ \scriptsize
+
+ \underline{Volume of the MD cell}
+ \begin{itemize}
+ \item $T=900\text{ K}$
+ \item $\alpha=2.0 \cdot 10^{-6}\text{ K}^{-1}$
+ \item $a = a_0(1+\alpha \Delta T)$
+ \item Plain Si$(T=0)$: $a_0=5.4575\text{ \AA}$
+ $\rightarrow a(900\text{ K})=5.4674\text{ \AA}$
+ \item C \hkl<1 0 0> in Si$(T=0)$: $a_0^{\text{avg}}=
+ \frac{1}{3}(a_0^x+a_0^y+a_0^z)=5.4605\text{ \AA}$
+ $\rightarrow a(900\text{ K})=5.4704{ \AA}$
+ \end{itemize}
+ Used in the 900 K simulations: 5.4705 \AA\\
+ Consider next thoughts as well!
+
+ \underline{Zero total momentum simulations}
+ \begin{itemize}
+ \item If C is randomly inserted there is a net total momentum
+ \item No correction in the temperature control routine of VASP?
+ \item Relax a Si:C configuration first (at T=0)
+ \item Use this configuration as the MD initial configuration
+ \end{itemize}
+ Two possibilities regarding volume which came to my mind:
+ \begin{enumerate}
+ \item Calculate and use an averaged $a_0$ (in each direction)
+ from the relaxed configuration.
+ Else there might be a preferred orientation for the defect.
+ \item On the other hand this might be important
+ for the way defects agglomerate.
+ Continue using the relaxation results.
+ \end{enumerate}
+ In both methods the corrections due to the non zero temperature
+ are applied!
+
+\end{slide}
+
\begin{slide}
{\large\bf
Molecular dynamics simulations (VASP)
}
- 2 C atoms in $2\times 2\times 2$ Type 2 supercell
+ 2 C atoms in $2\times 2\times 2$ Type 2 supercell at $450\,^{\circ}\text{C}$
\small
Molecular dynamics simulations (VASP)
}
- 10 C atoms in $3\times 3\times 3$ Type 2 supercell
+ 10 C atoms in $3\times 3\times 3$ Type 2 supercell at $450\,^{\circ}\text{C}$
\small
\end{slide}
+\begin{slide}
+
+ {\large\bf
+ Molecular dynamics simulations (VASP)
+ }
+
+ 1 C atom in $3\times 3\times 3$ Type 2 supercell at $900\,^{\circ}\text{C}$\\\\
+
+ Video \href{../video/md_01c_2333si_900_vasp.avi}{$\rhd_{\text{local}}$ } $|$
+ \href{http://www.physik.uni-augsburg.de/~zirkelfr/download/posic/md_01c_2333si_900_vasp.avi}{$\rhd_{\text{remote url}}$}\\\\
+
+ \begin{itemize}
+ \item Inserted C becomes a \hkl<0 0 1> interstitial after a few femto-seconds
+ \item {\color{red}There is a non-zero total momentum!}
+ \item Migration of the C atom not observed
+ \item C \hkl<0 0 1> configuration persists
+ \end{itemize}
+
+ Problem: Thermostat doesn't do momentum correction
+
+ TODO: Start MD using relaxed (at zero temperature) initial configuration
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Molecular dynamics simulations (VASP)
+ }
+
+ 10 C atoms in $3\times 3\times 3$ Type 2 supercell at $900\,^{\circ}\text{C}$
+
+ in progress ...
+
+\end{slide}
+
\begin{slide}
{\large\bf
Hohenberg-Kohn theorem
\small
-
\end{slide}
+\begin{slide}
+
+ {\large\bf
+ More theory ...
+ }
+
+ Transition state theory\\
+ ART,NEB ...
+
+ Group theory
+
+ \small
+
+\end{slide}
+
+\end{document}
\end{document}