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