beta version before spell check

diff --git a/posic/thesis/basics.tex b/posic/thesis/basics.tex
index ba62d82..4568141 100644 (file)
--- a/posic/thesis/basics.tex
+++ b/posic/thesis/basics.tex
@@ -669,7 +669,7 @@ In the modified version respective energies could be higher than the real ones d
 
 Structures of maximum configurational energy do not necessarily constitute saddle point configurations, i .e. the method does not guarantee to find the true minimum energy path.
 Whether a saddle point configuration and, thus, the minimum energy path is obtained by the CRT method, needs to be verified by caculating the respective vibrational modes.
 
 Structures of maximum configurational energy do not necessarily constitute saddle point configurations, i .e. the method does not guarantee to find the true minimum energy path.
 Whether a saddle point configuration and, thus, the minimum energy path is obtained by the CRT method, needs to be verified by caculating the respective vibrational modes.

-Modifications used to add the CRT feature to the VASP code and a short instruction on how to use it can be found in appendix \ref{app:patch_vasp}.
+Modifications used to add the CRT feature to the {\textsc vasp} code and a short instruction on how to use it can be found in appendix \ref{app:patch_vasp}.

 
 % todo - advantages of pw basis concenring hf forces
 
 
 % todo - advantages of pw basis concenring hf forces
 

diff --git a/posic/thesis/defects.tex b/posic/thesis/defects.tex
index 381dab5..cdc95a8 100644 (file)
--- a/posic/thesis/defects.tex
+++ b/posic/thesis/defects.tex
@@ -1659,7 +1659,7 @@ Thus, elevated temperatures might lead to thermodynamically unstable configurati
 
 % todo - sync with conclusion chapter
 
 
 % todo - sync with conclusion chapter
 

-These findings allow to draw conclusions on the mechanisms involved in the process of SiC conversion in Si.
+These findings allow to draw conclusions on the mechanisms involved in the process of SiC conversion in Si, which is elaborated in more detail within the comprehensive description in chapter~\ref{chapter:summary}.

 Agglomeration of C$_{\text{i}}$ is energetically favored and enabled by a low activation energy for migration.
 Although ion implantation is a process far from thermodynamic equilibrium, which might result in phases not described by the Si/C phase diagram, i.e. a C phase in Si, high activation energies are believed to be responsible for a low probability of the formation of C-C clusters.
 
 Agglomeration of C$_{\text{i}}$ is energetically favored and enabled by a low activation energy for migration.
 Although ion implantation is a process far from thermodynamic equilibrium, which might result in phases not described by the Si/C phase diagram, i.e. a C phase in Si, high activation energies are believed to be responsible for a low probability of the formation of C-C clusters.
 


@@ -1671,7 +1671,7 @@ The rearrangement is crucial to end up in a configuration of C atoms only occupy
 On the other hand, the conversion of some region of Si into SiC by \cs{} is accompanied by a reduction of the volume since SiC exhibits a \unit[20]{\%} smaller lattice constant than Si.
 The reduction in volume is compensated by excess Si$_{\text{i}}$ serving as building blocks for the surrounding Si host or a further formation of SiC.
 
 On the other hand, the conversion of some region of Si into SiC by \cs{} is accompanied by a reduction of the volume since SiC exhibits a \unit[20]{\%} smaller lattice constant than Si.
 The reduction in volume is compensated by excess Si$_{\text{i}}$ serving as building blocks for the surrounding Si host or a further formation of SiC.
 

-To conclude, precipitation occurs by successive agglomeration of C$_{\text{s}}$.
+To conclude, the available results suggest precipitation by successive agglomeration of C$_{\text{s}}$.

 However, the agglomeration and rearrangement of C$_{\text{s}}$ is only possible by mobile C$_{\text{i}}$, which has to be present at the same time.
 Accordingly, the process is governed by both, C$_{\text{s}}$ accompanied by Si$_{\text{i}}$ as well as C$_{\text{i}}$.
 It is worth to mention that there is no contradiction to results of the HREM studies \cite{werner96,werner97,eichhorn99,lindner99_2,koegler03}.
 However, the agglomeration and rearrangement of C$_{\text{s}}$ is only possible by mobile C$_{\text{i}}$, which has to be present at the same time.
 Accordingly, the process is governed by both, C$_{\text{s}}$ accompanied by Si$_{\text{i}}$ as well as C$_{\text{i}}$.
 It is worth to mention that there is no contradiction to results of the HREM studies \cite{werner96,werner97,eichhorn99,lindner99_2,koegler03}.

diff --git a/posic/thesis/md.tex b/posic/thesis/md.tex
index 3253d2b..43565f2 100644 (file)
--- a/posic/thesis/md.tex
+++ b/posic/thesis/md.tex
@@ -499,12 +499,20 @@ The insertion of high amounts of C into a small volume within a short period of
 % rt implantation + annealing
 Furthermore, C implanted at room temperature was found to be able to migrate towards the surface and form C-rich clusters in contrast to implantations at elevated temperatures, which form stable epitaxially aligned 3C-SiC precipitates \cite{serre95}.
 In simulation, low temperatures result in configurations of highly mobile \ci{} \hkl<1 0 0> DBs whereas elevated temperatures show configurations of \cs{}, which constitute an extremely stable configuration that is unlikely to migrate.
 % rt implantation + annealing
 Furthermore, C implanted at room temperature was found to be able to migrate towards the surface and form C-rich clusters in contrast to implantations at elevated temperatures, which form stable epitaxially aligned 3C-SiC precipitates \cite{serre95}.
 In simulation, low temperatures result in configurations of highly mobile \ci{} \hkl<1 0 0> DBs whereas elevated temperatures show configurations of \cs{}, which constitute an extremely stable configuration that is unlikely to migrate.

+%
+% added
+This likewise agrees to results of IBS experiments utilizing implantation temperatures of \degc{550}, which require annealing temperatures as high as \degc{1405} for C segregation due to the stability of \cs{} \cite{reeson87}.
+%

 Indeed, in the optimized recipe to form 3C-SiC by IBS \cite{lindner99}, elevated temperatures are used to improve the epitaxial orientation together with a low temperature implant to destroy stable SiC nanocrystals at the interface, which are unable to migrate during thermal annealing resulting in a rough surface.
 Furthermore, the improvement of the epitaxial orientation of the precipitate with increasing temperature in experiment perfectly conforms to the increasing occurrence of \cs{} in simulation.
 %
 Indeed, in the optimized recipe to form 3C-SiC by IBS \cite{lindner99}, elevated temperatures are used to improve the epitaxial orientation together with a low temperature implant to destroy stable SiC nanocrystals at the interface, which are unable to migrate during thermal annealing resulting in a rough surface.
 Furthermore, the improvement of the epitaxial orientation of the precipitate with increasing temperature in experiment perfectly conforms to the increasing occurrence of \cs{} in simulation.
 %

-% todo add sync here starting from werner96 (Similar, implan ...)
+% todo add sync here starting from strane93, werner96 ...
+Moreover, implantations of an understoichiometric dose into preamorphized Si followed by an annealing step at \degc{700} result in Si$_{1-x}$C$_x$ layers with C residing on substitutional Si lattice sites \cite{strane93}.
+For implantations of an understoichiometric dose into c-Si at room temperature followed by thermal annealing below and above \degc{700}, the formation of small C$_{\text{i}}$ agglomerates and SiC precipitates was observed respectively \cite{werner96}.
+However, increased implantation temperatures were found to be more efficient than postannealing methods resulting in the formation of SiC precipitates for implantations at \unit[450]{$^{\circ}$C} \cite{lindner99,lindner01}.

 %
 %

-At elevated temperatures, implanted C is therefore expected to occupy substitutionally usual Si lattice sites right from the start.
+Thus, at elevated temperatures, implanted C is expected to occupy substitutionally usual Si lattice sites right from the start.
+These findings, which are outlined in more detail within the comprehensive description in chapter~\ref{chapter:summary}, are in perfect agreement with previous results of the quantum-mechanical investigations.

 
 Thus, elevated temperatures are considered to constitute a necessary condition to deviate the system from equilibrium, as it is the case in IBS.
 It is concluded that precipitation occurs by successive agglomeration of C$_{\text{s}}$ as already proposed by Nejim et~al.~\cite{nejim95}.
 
 Thus, elevated temperatures are considered to constitute a necessary condition to deviate the system from equilibrium, as it is the case in IBS.
 It is concluded that precipitation occurs by successive agglomeration of C$_{\text{s}}$ as already proposed by Nejim et~al.~\cite{nejim95}.

diff --git a/posic/thesis/thesis.tex b/posic/thesis/thesis.tex
index acfcdb8..dd3eacc 100644 (file)
--- a/posic/thesis/thesis.tex
+++ b/posic/thesis/thesis.tex
@@ -28,6 +28,9 @@
 %\usepackage[resetlabels]{multibib}
 \newcites{pub}{List of publications}
 
 %\usepackage[resetlabels]{multibib}
 \newcites{pub}{List of publications}
 

+% box around verbatim text
+\usepackage{fancyvrb}
+

 % miller
 \usepackage{miller}
 
 % miller
 \usepackage{miller}
 

diff --git a/posic/thesis/vasp_patch.tex b/posic/thesis/vasp_patch.tex
index 500ec42..e495e8d 100644 (file)
--- a/posic/thesis/vasp_patch.tex
+++ b/posic/thesis/vasp_patch.tex
@@ -2,33 +2,48 @@
 \label{app:patch_vasp}
 
 \section{Description}
 \label{app:patch_vasp}
 
 \section{Description}

-The modifications to the VASP code allow to rotate all atom coordinates individually in the particle position evaluation routine of VASP.
-In that way constraints for every atom can be applied independently of the chosen basis.
-A patch against version 4.6 of the VASP code containing these modifications is available for download\footnote{http://www.physik.uni-augsburg.de/\~{}zirkelfr/download/posic/sd\_rot\_all-atoms.patch}.
+In the {\textsc vasp} code, the {\em selective dynamics} mode provides a feature to allow or constrain the change of each of the three coordinates for every single atom.
+By this, however, applied constraints are restricted to the chosen basis.
+For the investigation of migration pathways utilizing the constrained relaxation technique as detailed in section~\ref{section:basics:migration}, the required constraint not necessarily corresponds to one of the coordinate axes as defined by the basis, which, in turn, is determined to enable a construction within the supercell approach.

 
 

-\section{Usage}
+Thus, the functionality of the {\em selective dynamics} mode had to be extended by modifications in the particle position evaluation routine of {\textsc vasp}.
+These modifications allow for a rotation of all atom coordinates individually before respective constraints are applied and a following, final inverse transformation.
+In that way, constraints for every single atom can be applied independently of the chosen basis.
+A patch against version 4.6 of the {\textsc vasp} code containing these modifications is available for download\footnote{http://www.physik.uni-augsburg.de/\~{}zirkelfr/download/posic/sd\_rot\_all-atoms.patch}.

 
 

-Since this feature only makes sense in selective dynamics mode, it can be switched on by adding the word {\em Transformed} in front of the {\em selective dynamics} switch.
-This feature only works in direct mode.
+\section{Mode of operation}
+
+The extended capabilities can only be used within the {\em selective dynamics} mode.
+It is enabled by adding the word {\em transformed} in front of the {\em selective dynamics} switch.
+This feature only works in {\em direct} mode.

 Two values of angles need to be added after the extra flags of each atom.
 The first angle corresponds to the rotation of the basis about the $z$-axis.
 The second angle determines the rotation about the transformed $x$-axis, $x'$.
 All values have to be supplied in degrees.
 Two values of angles need to be added after the extra flags of each atom.
 The first angle corresponds to the rotation of the basis about the $z$-axis.
 The second angle determines the rotation about the transformed $x$-axis, $x'$.
 All values have to be supplied in degrees.

-All these information is given in the POSCAR file as can be seen in the follwing example:
-\begin{verbatim}
-cubic diamond                           
-   5.48000000000000     
-     2.9909698580839312    0.0039546630279804   -0.0039658085666586
-     0.0039548953566878    2.9909698596656376   -0.0039660323646892
-    -0.0039680658132861   -0.0039674231313905    2.9909994291263242
- 216   1
-Transformed selective dynamics
-Direct
- 0.994174 0.994174 -0.000408732 T F T 45 36.5145
- 0.182792 0.182792 0.981597 T F T -135 -5.95043
- ...
- 0.119896 0.119896 0.0385525 T F T -135 21.8036
-\end{verbatim}
-In case of the first atom the basis is transformed by a rotation of $45^{\circ}$ and $36.5145^{\circ}$ about the $z$ and $x'$ axis.
-Relaxation of this atom is constrained to the $y''$-axis.
+The entire information is given in the POSCAR file as can be seen in the example displayed in Fig.~\ref{fig:vasp_input}.
+\begin{figure}[t]
+\begin{Verbatim}[frame=single]
+cubic diamond
+ 5.429
+ 1.00000 0.00000 0.00000
+ 0.00000 1.00000 0.00000
+ 0.00000 0.00000 1.00000
+ 8
+transformed selective dynamics
+direct
+ 0.00000 0.00000 0.00000 T F T 45.0 30.0
+ 0.50000 0.50000 0.00000 T T T 0.0 0.0
+ 0.50000 0.00000 0.50000 T T T 0.0 0.0
+ 0.00000 0.50000 0.50000 T T T 0.0 0.0
+ 0.25000 0.25000 0.25000 T F T 135.0 -10.0
+ 0.75000 0.75000 0.25000 T T T 0.0 0.0
+ 0.75000 0.25000 0.75000 T T T 0.0 0.0
+ 0.25000 0.75000 0.75000 T T T 0.0 0.0
+\end{Verbatim}
+\caption{Example {\textsc vasp} input file utilizing the {\em transformed selective dynamics} mode of operation.}
+\label{fig:vasp_input}
+\end{figure}
+In case of the first atom, the basis is transformed by a rotation of $45^{\circ}$ and $30^{\circ}$ about the $z$ and $x'$ axis.
+The basis of the fifth atom is likewise rotated by $135^{\circ}$ and $-10^{\circ}$ respectively.
+Relaxation of both atoms is only allowed within the plane perpendicular to the $y''$-axis.