From: hackbard <hackbard@sage.physik.uni-augsburg.de>
Date: Wed, 14 Oct 2009 17:12:53 +0000 (+0200)
Subject: updated formation energies + new thoughts about interstitials
X-Git-Url: https://hackdaworld.org/gitweb/?a=commitdiff_plain;h=48c53df439a14a13f49a66f4eeaf12445c3d0a03;p=lectures%2Flatex.git

updated formation energies + new thoughts about interstitials
---

diff --git a/posic/talks/upb-ua-xc.tex b/posic/talks/upb-ua-xc.tex
index bdab507..f1f60f4 100644
--- a/posic/talks/upb-ua-xc.tex
+++ b/posic/talks/upb-ua-xc.tex
@@ -2124,22 +2124,24 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
   }
   & \hkl<1 1 -1> & \hkl<2 2 0> & \hkl<3 3 -1> & \hkl<4 4 0>\\
  \hline
- \hkl<0 0 -1> & 6.23514\newline {\color{blue}6.23514} 
-              & 4.65214\newline {\color{blue}4.65014} 
-              & 5.97314\newline {\color{blue}5.97314}
-              & 6.45514\newline {\color{blue}6.45714} \\
+ \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> & 6.65114\newline {\color{blue}6.65114} 
-             & 4.78514\newline {\color{blue}4.78314} 
-             & 6.53614\newline {\color{blue}6.53614}
-             & 6.18914\newline {\color{blue}6.18914} \\
+ \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> & 4.07014\newline alkmene
-                          & 4.93814
-                          & 5.72914
-                          & 6.00214\\
+ \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> & 3.93014 & 4.43414 & 6.02814 & 6.02414 \\
+ \hkl<-1 0 0>, \hkl<0 -1 0> & 3.92 & 4.43 & 6.02 & 6.02 \\
+ \hline
+ Vacancy & ... & ... & ... & ... \\
  \hline
  \end{tabular}
 
@@ -2202,21 +2204,23 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
   Combination of defects
  }
 
- \begin{tabular}{|l|l|l|l|}
+ \begin{tabular}{|l|l|l|l|l|l|}
+ \hline
+ & 2 & 3 & 4 & 5 & 6 \\
  \hline
- & 2 & 3 & 4 \\
+\hkl<0 0 -1> & 6.23 & 5.16 & 6.23 & ... & 4.65\\
  \hline
-\hkl<0 0 -1> & 6.23 & 5.16 & 6.23 \\
+\hkl<0 0 1> & 6.64 & 6.31 & ... & ... & 4.78 \\
  \hline
-\hkl<0 0 1> & 6.64 & 6.31 & ... \\
+\hkl<1 0 0> & 4.06 & 6.13 & 6.21 & ... & 4.93 \\
  \hline
-\hkl<1 0 0> & 4.06 & 6.13 & ... \\
+\hkl<-1 0 0> & \hkl<0 -1 0> & 4.41 & ... & ... & 4.43 \\
  \hline
-\hkl<-1 0 0> & as \hkl<0 -1 0> & 4.41 & ... \\
+\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> & as \hkl<1 0 0> & 5.95 & as \hkl<-1 0 0> \\
+\hkl<0 -1 0> & 3.92 & ... & \hkl<1 0 0> & \hkl<1 0 0> & \hkl <-1 0 0> \\
  \hline
-\hkl<0 -1 0> & 3.92 & ... & as \hkl<1 0 0>\\
+Vacancy & ... & ... & ... & ... & ... \\
  \hline
  \end{tabular}
 
@@ -2263,6 +2267,49 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
  
 \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
@@ -2340,6 +2387,10 @@ $z,x'$-axis rotation: $45.0^{\circ}$, $0.0^{\circ}$
  \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}