mirror of
https://github.com/triqs/dft_tools
synced 2024-12-25 13:53:40 +01:00
101 lines
4.6 KiB
ReStructuredText
101 lines
4.6 KiB
ReStructuredText
.. _convgeneralhk:
|
|
|
|
A general H(k)
|
|
==============
|
|
|
|
In addition to the more extensive Wien2k, VASP, and W90 converters,
|
|
:program:`DFTTools` contains also a light converter. It takes only
|
|
one inputfile, and creates the necessary hdf outputfile for
|
|
the DMFT calculation. The header of this input file has a defined
|
|
format, an example is the following (do not use the text/comments in your
|
|
input file):
|
|
|
|
.. literalinclude:: images_scripts/case.hk
|
|
|
|
The lines of this header define
|
|
|
|
#. Number of :math:`\mathbf{k}`-points used in the calculation
|
|
#. Electron density for setting the chemical potential
|
|
#. Number of total atomic shells in the hamiltonian matrix. In short,
|
|
this gives the number of lines described in the following. IN the
|
|
example file give above this number is 2.
|
|
#. The next line(s) contain four numbers each: index of the atom, index
|
|
of the equivalent shell, :math:`l` quantum number, dimension
|
|
of this shell. Repeat this line for each atomic shell, the number
|
|
of the shells is given in the previous line.
|
|
|
|
In the example input file given above, we have two inequivalent
|
|
atomic shells, one on atom number 1 with a full d-shell (dimension 5),
|
|
and one on atom number 2 with one p-shell (dimension 3).
|
|
|
|
Other examples for these lines are:
|
|
|
|
#. Full d-shell in a material with only one correlated atom in the
|
|
unit cell (e.g. SrVO3). One line is sufficient and the numbers
|
|
are `1 1 2 5`.
|
|
#. Full d-shell in a material with two equivalent atoms in the unit
|
|
cell (e.g. FeSe): You need two lines, one for each equivalent
|
|
atom. First line is `1 1 2 5`, and the second line is
|
|
`2 1 2 5`. The only difference is the first number, which tells on
|
|
which atom the shell is located. The second number is the
|
|
same in both lines, meaning that both atoms are equivalent.
|
|
#. t2g orbitals on two non-equivalent atoms in the unit cell: Two
|
|
lines again. First line is `1 1 2 3`, second line `2 2 2 3`. The
|
|
difference to the case above is that now also the second number
|
|
differs. Therefore, the two shells are treated independently in
|
|
the calculation.
|
|
#. d-p Hamiltonian in a system with two equivalent atoms each in
|
|
the unit cell (e.g. FeSe has two Fe and two Se in the unit
|
|
cell). You need for lines. First line `1 1 2 5`, second
|
|
line
|
|
`2 1 2 5`. These two lines specify Fe as in the case above. For the p
|
|
orbitals you need line three as `3 2 1 3` and line four
|
|
as `4 2 1 3`. We have 4 atoms, since the first number runs from 1 to 4,
|
|
but only two inequivalent atoms, since the second number runs
|
|
only form 1 to 2.
|
|
|
|
Note that the total dimension of the hamiltonian matrices that are
|
|
read in is the sum of all shell dimensions that you specified. For
|
|
example number 4 given above we have a dimension of 5+5+3+3=16. It is important
|
|
that the order of the shells that you give here must be the same as
|
|
the order of the orbitals in the hamiltonian matrix. In the last
|
|
example case above the code assumes that matrix index 1 to 5
|
|
belongs to the first d shell, 6 to 10 to the second, 11 to 13 to
|
|
the first p shell, and 14 to 16 the second p shell.
|
|
|
|
#. Number of correlated shells in the hamiltonian matrix, in the same
|
|
spirit as line 3.
|
|
|
|
#. The next line(s) contain six numbers: index of the atom, index
|
|
of the equivalent shell, :math:`l` quantum number, dimension
|
|
of the correlated shells, a spin-orbit parameter, and another
|
|
parameter defining interactions. Note that the latter two
|
|
parameters are not used at the moment in the code, and only kept
|
|
for compatibility reasons. In our example file we use only the
|
|
d-shell as correlated, that is why we have only one line here.
|
|
|
|
#. The last line contains several numbers: the number of irreducible
|
|
representations, and then the dimensions of the irreps. One
|
|
possibility is as the example above, another one would be 2
|
|
2 3. This would mean, 2 irreps (eg and t2g), of dimension 2 and 3,
|
|
resp.
|
|
|
|
After these header lines, the file has to contain the Hamiltonian
|
|
matrix in orbital space. The standard convention is that you give for
|
|
each :math:`\mathbf{k}`-point first the matrix of the real part, then the
|
|
matrix of the imaginary part, and then move on to the next :math:`\mathbf{k}`-point.
|
|
|
|
The converter itself is used as::
|
|
|
|
from triqs_dft_tools.converters.hk_converter import *
|
|
Converter = HkConverter(filename = hkinputfile)
|
|
Converter.convert_dft_input()
|
|
|
|
where :file:`hkinputfile` is the name of the input file described
|
|
above. This produces the hdf file that you need for a DMFT calculation.
|
|
|
|
For more options of this converter, have a look at the
|
|
:ref:`refconverters` section of the reference manual.
|
|
|
|
|