The static code has three required and two optional
input files. The required files are
- SKIN
(Slater-Koster INput)
The SKIN file is the basic input for the static program. It
gives the pointers to the tight-binding parametrization file,
the space group file, the optional k-point file. It also has
the input for each structure to be studied, including primitive vectors, including possible strains of the unit cell
and the atomic positions. Rather than explain the components
of these files, we refer the user to the appropriate parts of
the examples.
Starting with version 1.10, we provide a Perl-script SKIN
file generator, skingen, which
generates SKIN files for a wide class of problems.
- Parameter
File
The tight-binding parameter file. This may be obtained from
the Tight-Binding
Parameters Database, if a file for the system of interest
is available. Contact the authors to see
about the development of parametrizations for elements or
compounds which have yet to be determined. Given the possible
number of compounds available, this has to be a process
driven by the interests of our users and/or our own research
interests. The relative or absolute location of the parameter
file must be entered in the appropriate location in the SKIN
file.
- Space Group
File
The space group file. Space group files for many crystal
structures are collected in the Crystal Lattice
Structures database. Others can be constructed from the
International Tables for Crystallography according to the space
group construction rules. If you have no idea of the
symmetry, or for calculations involving an isolated cluster of
atoms, you can use this identity+inversion space group
file, which contains only the identity operation and the
inversion operator. The inversion operator is allowed because
the eigenvalues of a Hamiltonian always obey time-reversal
symmetry, that is, eign(-k) =
eign(k) for every state
eign at any wave-vector k.
Additionally, we provide sample files for the elastic constants here.
The purpose of the space group file is to reduce the number
of k-points needed in the calculation by exploiting the
symmetry of the crystal. Thus, for example, in an isolated
cluster, where the calculation need be done for only one
k-point, you need use only the identity space group file
- k-point File
(optional)
The first optional
file is the k-point mesh file. K-point information is
mandatory, but it can be read in as part of the SKIN file, as
in Example 2, or, if
desired, the k-points can be read from an external file, as
in, e.g., Example 1
or Example 3. Note
that for an isolated cluster you may use this single k-point file.
TWEAKS file
(optional)
If it exists, the TWEAKS file tells the program
to print certain diagnostic information during execution.
Typically the information is printed in the SKOUT file.
The TWEAKS file contains several lines of input.
Each line is either a command or a number. The current
commands are:
PRINT_PARAMETERS: if this line is present,
the Slater-Koster onsite, hopping, and overlap parameters are
printed in SKOUT.
PRINT_DERIVATIVE_PAR: like the above, but
the derivative of these parameters with respect to volume is
printed. Useful only when the pressure is computed, e.g., in
Mode 2 or Mode 4 calculations.
PRINT_MATRIX: if present, the next line is
read. If it is an integer, i, then non-zero values of the
Hamiltonian and Overlap matrices are printed in
SKOUT.
PRINT_PROGRESS: if set, the program prints a
line to standard output (not SKOUT) every time it
starts the calculation of the eigenvalues of a new k-point.
PRINT_DIMENSIONS: if present, prints the
dimensions set in the P[1,2,3]
files to SKOUT. This is useful if you want to
see if a specific executable can handle an new problem, or if
you will have to redimension and recompile the code.
static Home
Page Introduction
Installation List of Files Usage Input Files Output Files Trouble Shooting Appendix
Current URL: http://esd.cos.gmu.edu/tb/static/input_files.html