From: hackbard Date: Wed, 14 Oct 2009 17:12:53 +0000 (+0200) Subject: updated formation energies + new thoughts about interstitials X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?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}