X-Git-Url: https://hackdaworld.org/gitweb/?a=blobdiff_plain;f=posic%2Ftalks%2Fupb-ua-xc.tex;h=63139eed075978ae523e5a4e7b5d9e2fdc52beff;hb=ed6682d70ad5a945b3c518c928445be3f70d4016;hp=f1f60f4c8a9055f192e4163ba9982f28caf54f65;hpb=48c53df439a14a13f49a66f4eeaf12445c3d0a03;p=lectures%2Flatex.git

diff --git a/posic/talks/upb-ua-xc.tex b/posic/talks/upb-ua-xc.tex
index f1f60f4..63139ee 100644
--- a/posic/talks/upb-ua-xc.tex
+++ b/posic/talks/upb-ua-xc.tex
@@ -1959,6 +1959,29 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
    in the $3\times 3\times 3$ Type 2 supercell
  }
 
+ \begin{minipage}{6cm}
+ Method:
+ \begin{itemize}
+  \item Starting configuration:\\
+        C bond centered
+  \item CRT towards \hkl<0 0 -1> configuration
+  \item Spin polarized calculations
+ \end{itemize}
+ Results:\\
+ Video \href{../video/c_im_00-1_vasp.avi}{$\rhd_{\text{local}}$ } $|$
+ \href{http://www.physik.uni-augsburg.de/~zirkelfr/download/posic/c_im_00-1_vasp.avi}{$\rhd_{\text{remote url}}$}
+ \begin{itemize}
+  \item Still abrupt changes in configuration and energy 
+  \item Migration barrier $>$ 1 eV
+  \item I bet it's not reversible!
+  \item {\color{red}Final run in progress}
+ \end{itemize} 
+ \end{minipage}
+ \begin{minipage}{6cm}
+ \includegraphics[width=6cm]{c_im_001_mig_vasp.ps}
+ \includegraphics[width=6cm]{c_im_001_mig_rc_vasp.ps}
+ \end{minipage}
+
 \end{slide}
 
 \begin{slide}
@@ -1969,6 +1992,19 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
  }
 
  \includegraphics[width=6cm]{c_00-1_0-10_mig_vasp.ps}
+ \includegraphics[width=6cm]{c_00-1_0-10_mig_dis_vasp.ps}
+
+ Calculations without spin:\\
+ Video \href{../video/c_00-1_0-10_vasp.avi}{$\rhd_{\text{local}}$ } $|$
+ \href{http://www.physik.uni-augsburg.de/~zirkelfr/download/posic/c_00-1_0-10_vasp.avi}{$\rhd_{\text{remote url}}$} ... see the whole truth! WAAAAH!!!
+ \begin{itemize}
+  \item Refined starting from 70\% due to
+        abrubt jumps in energy and configuration 
+  \item Displacement from 80 to 85\% disastrous
+  \item Subsequent displacements too large
+ \end{itemize}
+
+ Waiting for spin polarized calculations before deciding what to do ...
 
 \end{slide}
 
@@ -2103,6 +2139,50 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
  
 \end{slide}
 
+\begin{slide}
+
+ {\large\bf\boldmath
+  Carbon point defects in silicon
+ }
+ 
+ \begin{minipage}{3.2cm}
+ \underline{C bond centered}
+ \begin{itemize}
+  \item $E_{\text{f}}=4.10\text{ eV}$
+ \end{itemize}
+ \includegraphics[width=3cm]{c_pd_vasp/bc_2333.eps}
+ \underline{\hkl<1 1 0> interstitial}
+ \begin{itemize}
+  \item $E_{\text{f}}=3.60\text{ eV}$
+ \end{itemize}
+ \includegraphics[width=3cm]{c_pd_vasp/110_2333.eps}
+ \end{minipage}
+ \begin{minipage}{4.5cm}
+ \begin{center}
+ \includegraphics[height=8cm]{c_pd_vasp/110_2333_ksl.ps}
+ {\scriptsize \hkl<1 1 0> interstitial}
+ \end{center}
+ \end{minipage}
+ \begin{minipage}{4.5cm}
+ \begin{center}
+ \includegraphics[height=8cm]{c_pd_vasp/bc_2333_ksl.ps}
+ {\scriptsize C bond centered}
+ \end{center}
+ \end{minipage}
+ 
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf\boldmath
+  Carbon point defects in silicon
+ }
+
+ The hexagonal and tetrahedral C configurations both relax into the
+ \hkl<0 0 1> interstitial configuration!
+ 
+\end{slide}
+
 \begin{slide}
 
  {\large\bf\boldmath
@@ -2112,12 +2192,13 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
  \begin{itemize}
   \item Supercell: $3\times 3\times 3$ Type 2
   \item Starting configuration: \hkl<0 0 -1> C-Si interstitial
+        ($E_{\text{f}}=3.15\text{ eV}$)
   \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}|}
+ \begin{tabular}{|l|p{2.0cm}|p{1.8cm}|p{1.8cm}|p{1.8cm}|}
  \hline
   {\scriptsize
   \backslashbox{2nd interstitial}{Distance $[\frac{a}{4}]$}
@@ -2141,7 +2222,7 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
  \hline
  \hkl<-1 0 0>, \hkl<0 -1 0> & 3.92 & 4.43 & 6.02 & 6.02 \\
  \hline
- Vacancy & ... & ... & ... & ... \\
+ Vacancy & 1.39 ($\rightarrow\text{ C}_{\text{S}}$)& 5.81 & 5.47 & 6.50 \\
  \hline
  \end{tabular}
 
@@ -2204,25 +2285,37 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
   Combination of defects
  }
 
+ \small
+
+ Initial C \hkl<0 0 -1> insterstital at: $\frac{1}{4}\hkl<1 1 1>$
+
  \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\\
+C \hkl<0 0 -1> & 6.23/-0.08 & 5.16/-1.15 & 6.23/-0.08 & 6.35/0.04 & 4.65/-1.66\\
  \hline
-\hkl<0 0 1> & 6.64 & 6.31 & ... & ... & 4.78 \\
+C \hkl<0 0 1> & 6.64/0.34 & 6.31/0.01 & 4.26/-2.05 & 6.57/0.26 & 4.78/-1.53 \\
  \hline
-\hkl<1 0 0> & 4.06 & 6.13 & 6.21 & ... & 4.93 \\
+C \hkl<1 0 0> & 4.06/-2.25 & 6.13/-0.17 & 6.21/-0.10 & 6.03/-0.27 & 4.93/-1.38 \\
  \hline
-\hkl<-1 0 0> & \hkl<0 -1 0> & 4.41 & ... & ... & 4.43 \\
+C \hkl<-1 0 0> & \hkl<0 -1 0> & 4.41/-1.90 & 4.06/-2.25 & 6.19/-0.12 & 4.43/-1.88 \\
  \hline
-\hkl<0 1 0> & \hkl<1 0 0> & 5.95 & \hkl<-1 0 0> & \hkl<-1 0 0> & \hkl<1 0 0> \\
+C \hkl<0 1 0> & \hkl<1 0 0> & 5.95/-0.36 & \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> \\
+C \hkl<0 -1 0> & 3.92/-2.39 & 4.15/-2.16 & \hkl<1 0 0> & \hkl<1 0 0> & \hkl <-1 0 0> \\
  \hline
-Vacancy & ... & ... & ... & ... & ... \\
+Vacancy & 1.39/-5.39 ($\rightarrow\text{ C}_{\text{S}}$) & 6.19/-0.59 & 3.65/-3.14 & 6.24/-0.54 & 6.50/-0.50 \\
  \hline
- \end{tabular}
+ \end{tabular}\\[0.2cm]
+ Energies: $x/y$\\
+ $x$: Defect formation energy of the complex\\
+ $y$:
+  $E_{\text{f}}^{\text{defect combination}}-
+   E_{\text{f}}^{\text{isolated C \hkl<0 0 -1>}}-
+   E_{\text{f}}^{\text{isolated 2nd defect}}
+  $\\
+  That is: If $y<0$ $\rightarrow$ favored compared to far-off isolated defects
 
 \end{slide}
 
@@ -2234,7 +2327,7 @@ Vacancy & ... & ... & ... & ... & ... \\
 
  \small
 
- Supercell size: $2$ - $2000 \cdot 10^{-21}\text{ cm}^3$
+ Supercell size: $2$ -- $2000 \cdot 10^{-21}\text{ cm}^3$
 
  \underline{After crystal growth}
  \begin{itemize}
@@ -2273,11 +2366,11 @@ Vacancy & ... & ... & ... & ... & ... \\
   Reminder (just for me to keep in mind ...)
  }
 
- \scriptsize
+ \small
 
  \underline{Volume of the MD cell}
  \begin{itemize}
-  \item $T=900\text{ K}$
+  \item $T=450, 900, 1400\text{ K}$ - (no melting, N\underline{V}T!)
   \item $\alpha=2.0 \cdot 10^{-6}\text{ K}^{-1}$
   \item $a = a_0(1+\alpha \Delta T)$
   \item Plain Si$(T=0)$: $a_0=5.4575\text{ \AA}$
@@ -2286,27 +2379,18 @@ Vacancy & ... & ... & ... & ... & ... \\
         \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!
+ Used in first 900 K simulations: 5.4705 \AA\\
+ BUT: Better use plain Si lattice constant! (only local distortions)\\
+ $\Rightarrow a(1400\text{ K})=5.4728\text{ \AA}$
 
  \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 Relax a Si:C configuration first
+        (at T=0, no volume relaxation, scaled volume)
   \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}