From 8b6b337baf9ae3efa492f298eb5c813b20a77664 Mon Sep 17 00:00:00 2001 From: hackbard Date: Thu, 16 Jun 2011 17:51:23 +0200 Subject: [PATCH 1/1] more tonight or tomorrow --- posic/publications/sic_prec_merge.tex | 29 +++++++++------------------ 1 file changed, 10 insertions(+), 19 deletions(-) diff --git a/posic/publications/sic_prec_merge.tex b/posic/publications/sic_prec_merge.tex index 0e1daf5..79a257d 100644 --- a/posic/publications/sic_prec_merge.tex +++ b/posic/publications/sic_prec_merge.tex @@ -309,7 +309,7 @@ For the latter case a migration path, which involves a C$_{\text{i}}$ \hkl<1 1 0 \caption{Migration barrier and structures of the \hkl[0 0 -1] DB (left) to the \hkl[0 -1 0] DB (right) transition involving the \hkl[1 1 0] DB (center) configuration. Migration simulations were performed utilizing time constants of \unit[1]{fs} (solid line) and \unit[100]{fs} (dashed line) for the Berendsen thermostat.} \label{fig:mig} \end{figure} -Approximately \unit[2.24]{eV} are needed to turn the C$_{\text{i}}$ \hkl[0 0 -1] DB into the C$_{\text{i}}$ \hkl[1 1 0] DB located at the neighbored lattice site in \hkl[1 1 -1] direction. +The activation energy of approximately \unit[2.24]{eV} is needed to turn the C$_{\text{i}}$ \hkl[0 0 -1] DB into the C$_{\text{i}}$ \hkl[1 1 0] DB located at the neighbored lattice site in \hkl[1 1 -1] direction. Another barrier of \unit[0.90]{eV} exists for the rotation into the C$_{\text{i}}$ \hkl[0 -1 0] DB configuration for the path obtained with a time constant of \unit[100]{fs} for the Berendsen thermostat. Roughly the same amount would be necessary to excite the C$_{\text{i}}$ \hkl[1 1 0] DB to the BC configuration (\unit[0.40]{eV}) and a successive migration into the \hkl[0 0 1] DB configuration (\unit[0.50]{eV}) as displayed in our previous study\cite{zirkelbach10}. The former diffusion process, however, would more nicely agree with the ab initio path, since the migration is accompanied by a rotation of the DB orientation. @@ -318,11 +318,19 @@ By considering a two step process and assuming equal preexponential factors for Accordingly, the effective barrier of migration of C$_{\text{i}}$ is overestimated by a factor of 2.4 to 3.5 compared to the highly accurate quantum-mechanical methods. This constitutes a serious limitation that has to be taken into account for modeling the C-Si system using the otherwise quite promising EA potential. +\section{Quantum-mechanical investigations of defect combinations and related diffusion processes} +\label{sec:qm} +Qm stuff ... more accurate, less efficient ... some small probs that ... +or in intro ... +\subsection{Mobility of silicon defects} - +% todo- where to put mobility +Concerning the mobility of the ground state Si$_{\text{i}}$, an activation energy of \unit[0.67]{eV} for the transition of the Si$_{\text{i}}$ \hkl[0 1 -1] to \hkl[1 1 0] DB located at the neighbored Si lattice site in \hkl[1 1 -1] direction is obtained by first-principles calculations. +Further quantum-mechanical investigations revealed a barrier of \unit[0.94]{eV} for the Si$_{\text{i}}$ \hkl[1 1 0] DB to Si$_{\text{i}}$ H, \unit[0.53]{eV} for the Si$_{\text{i}}$ \hkl[1 1 0] DB to Si$_{\text{i}}$ T and \unit[0.35]{eV} for the Si$_{\text{i}}$ H to Si$_{\text{i}}$ T transition. +These are of the same order of magnitude than values derived from other ab initio studies\cite{bloechl93,sahli05}. \section{Excursus: Competition of C$_{\text{i}}$ and C$_{\text{s}}$-Si$_{\text{i}}$} @@ -364,23 +372,6 @@ In either case, no configuration more favorable than the C$_{\text{i}}$ \hkl<1 0 Thus, a proper description with respect to the relative energies of formation is assumed for the EA potential. - - - - -\section{Quantum-mechanical investigations of defect combinations and related diffusion processes} -\label{sec:qm} - -Qm stuff ... more accurate, less efficient ... some small probs that ... -or in intro ... - -\subsection{Mobility of silicon defects} - -% todo- where to put mobility -Concerning the mobility of the ground state Si$_{\text{i}}$, an activation energy of \unit[0.67]{eV} for the transition of the Si$_{\text{i}}$ \hkl[0 1 -1] to \hkl[1 1 0] DB located at the neighbored Si lattice site in \hkl[1 1 -1] direction is obtained by first-principles calculations. -Further quantum-mechanical investigations revealed a barrier of \unit[0.94]{eV} for the Si$_{\text{i}}$ \hkl[1 1 0] DB to Si$_{\text{i}}$ H, \unit[0.53]{eV} for the Si$_{\text{i}}$ \hkl[1 1 0] DB to Si$_{\text{i}}$ T and \unit[0.35]{eV} for the Si$_{\text{i}}$ H to Si$_{\text{i}}$ T transition. -These are of the same order of magnitude than values derived from other ab initio studies\cite{bloechl93,sahli05}. - \section{Classical potential calculations on the SiC precipitation in Si} \label{sec:md} -- 2.20.1