mirror of
https://github.com/triqs/dft_tools
synced 2024-12-21 20:03:41 +01:00
docs (conversion): update VASP-conversion documentation
This commit is contained in:
Oleg E. Peil
Manuel
parent
c2dfc3fb6c
commit
9081ce634c
@ -189,54 +189,98 @@ Interface with VASP
|
||||
yet publicly released. The documentation may, thus, be subject to changes
|
||||
before the final release.
|
||||
|
||||
Note that this VASP interface relies on new options introduced since version
|
||||
5.4.x.
|
||||
*Limitations of the alpha-version:*
|
||||
|
||||
Additionally, the interface only works correctly if the k-point symmetries
|
||||
are turned off during the VASP run (ISYM=-1).
|
||||
* The interface works correctly only if the k-point symmetries
|
||||
are turned off during the VASP run (ISYM=-1).
|
||||
|
||||
The output of raw (non-normalized) projectors is controlled by an INCAR option
|
||||
LOCPROJ whose complete syntax is described in the VASP documentaion.
|
||||
* Generation of projectors for k-point lines (option `Lines` in KPOINTS)
|
||||
needed for Bloch spectral function calculations is not possible at the moment.
|
||||
|
||||
The definition of a projector set starts with specifying which sites
|
||||
and which local states we are going to project onto.
|
||||
This information is provided by option LOCPROJ
|
||||
* The interface currently supports only collinear-magnetism calculation
|
||||
(this implis no spin-orbit coupling) and
|
||||
spin-polarized projectors have not been tested.
|
||||
|
||||
A detailed description of the VASP converter tool PLOVasp can be found
|
||||
in :ref:`plovasp`. Here, a quick-start guide is presented.
|
||||
|
||||
The VASP interface relies on new options introduced since version
|
||||
5.4.x. In particular, a new INCAR-option `LOCPROJ`
|
||||
and new `LORBIT` modes 13 and 14 have been added.
|
||||
|
||||
Option `LOCPROJ` selects a set of localized projectors that will
|
||||
be written to file `LOCPROJ` after a successful VASP run.
|
||||
A projector set is specified by site indices,
|
||||
labels of the target local states, and projector type:
|
||||
|
||||
| `LOCPROJ = <sites> : <shells> : <projector type>`
|
||||
|
||||
where `<sites>` represents a list of site indices separated by spaces,
|
||||
with the indices corresponding to the site position in the POSCAR file;
|
||||
`<shells>` specifies local states (e.g. :math:`s`, :math:`p`, :math:`d`,
|
||||
:math:`d_{x^2-y^2}`, etc.);
|
||||
`<shells>` specifies local states (see below);
|
||||
`<projector type>` chooses a particular type of the local basis function.
|
||||
The recommended projector type is `Pr 2`.
|
||||
|
||||
Some projector types also require parameters `EMIN`, `EMAX` in INCAR to
|
||||
be set to define an (approximate) energy window corresponding to the
|
||||
valence states.
|
||||
The allowed labels of the local states defined in terms of cubic
|
||||
harmonics are:
|
||||
|
||||
When either a self-consistent (`ICHARG < 10`) or a non-self-consistent
|
||||
(`ICHARG >= 10`) calculation is done VASP produces file `LOCPROJ` which
|
||||
will serve as the main input for the conversion routine.
|
||||
* Entire shells: `s`, `p`, `d`, `f`
|
||||
|
||||
* `p`-states: `py`, `pz`, `px`
|
||||
|
||||
* `d`-states: `dxy`, `dyz`, `dz2`, `dxz`, `dx2-y2`
|
||||
|
||||
* `f`-states: `fy(3x2-y2)`, `fxyz`, `fyz2`, `fz3`,
|
||||
`fxz2`, `fz(x2-y2)`, `fx(x2-3y2)`.
|
||||
|
||||
For projector type `Pr 2`, one should also set `LORBIT = 14` in INCAR
|
||||
and provide parameters `EMIN`, `EMAX` which, in this case, define an
|
||||
energy range (window) corresponding to the valence states. Note that as in the case
|
||||
of DOS calculation the position of the valence states depends on the
|
||||
Fermi level.
|
||||
|
||||
For example, in case of SrVO3 one may first want to perform a self-consistent
|
||||
calculation, then set `ICHARGE = 1` and add the following additional
|
||||
lines into INCAR (provided that V is the second ion in POSCAR):
|
||||
|
||||
| `EMIN = 3.0`
|
||||
| `EMAX = 8.0`
|
||||
| `LORBIT = 14`
|
||||
| `LOCPROJ = 2 : d : Pr 2`
|
||||
|
||||
The energy range does not have to be precise. Important is that it has a large
|
||||
overlap with valence bands and no overlap with semi-core or high unoccupied states.
|
||||
|
||||
Conversion for the DMFT self-consistency cycle
|
||||
""""""""""""""""""""""""""""""""""""""""""""""
|
||||
|
||||
In order to use the projectors generated by VASP for defining an
|
||||
impurity problem they must be processed, i.e. normalized, possibly
|
||||
transformed, and then converted to a format suitable for DFT_tools scripts.
|
||||
The projectors generated by VASP require certain post-processing before
|
||||
they can be used for DMFT calculations. The most important step is to normalize
|
||||
them within an energy window that selects band states relevant for the impurity
|
||||
problem. Note that this energy window is different from the one described above
|
||||
and it must be chosen independently of the energy
|
||||
range given by `EMIN, EMAX` in INCAR.
|
||||
|
||||
Currently, it is necessary to add the Fermi energy by hand as the fifth value
|
||||
in the first line of the LOCPROJ file before the next steps can be executed.
|
||||
Post-processing of `LOCPROJ` data is generally done as follows:
|
||||
|
||||
The processing of projectors is performed by the program :program:`plovasp`
|
||||
invoked as
|
||||
#. Prepare an input file `<name>.cfg` (e.g., `plo.cfg`) that describes the definition
|
||||
of your impurity problem (more details below).
|
||||
|
||||
| `plovasp <plo.cfg>`
|
||||
#. Extract the value of the Fermi level from OUTCAR and paste at the end of
|
||||
the first line of LOCPROJ.
|
||||
|
||||
where `<plo.cfg>` is a input file controlling the conversion of projectors.
|
||||
#. Run :program:`plovasp` with the input file as an argument, e.g.:
|
||||
|
||||
The format of input file `<plo.cfg>` is described in details in
|
||||
| `plovasp plo.cfg`
|
||||
|
||||
This requires that the TRIQS paths are set correctly (see Installation
|
||||
of TRIQS).
|
||||
|
||||
If everything goes right one gets files `<name>.ctrl` and `<name>.pg1`.
|
||||
These files are needed for the converter that will be invoked in your
|
||||
DMFT script.
|
||||
|
||||
The format of input file `<name>.cfg` is described in details in
|
||||
:ref:`plovasp`. Here we just give a simple example for the case
|
||||
of SrVO3:
|
||||
|
||||
@ -257,7 +301,7 @@ Option **TRANSFORM** is optional but here it is specified to extract
|
||||
only three :math:`t_{2g}` orbitals out of five `d` orbitals given by
|
||||
:math:`l = 2`.
|
||||
|
||||
For the conversion to a h5 file we use on the python level (in analogy to the Wien2kConverter)::
|
||||
The conversion to a h5-file is performed in the same way as for Wien2TRIQS::
|
||||
|
||||
from triqs_dft_tools.converters.vasp_converter import *
|
||||
Converter = VaspConverter(filename = filename)
|
||||
@ -265,12 +309,15 @@ For the conversion to a h5 file we use on the python level (in analogy to the Wi
|
||||
|
||||
As usual, the resulting h5-file can then be used with the SumkDFT class.
|
||||
|
||||
Note that the automatic detection of the correct blockstructure might fail for VASP inputs.
|
||||
This can be circumvented by increase the :class:`SumkDFT <dft.sumk_dft.SumkDFT>` threshold to e.g.::
|
||||
Note that the automatic detection of the correct block structure might
|
||||
fail for VASP inputs.
|
||||
This can be circumvented by setting a bigger value of the threshold in
|
||||
:class:`SumkDFT <dft.sumk_dft.SumkDFT>`, e.g.::
|
||||
|
||||
SK.analyse_block_structure(threshold = 1e-4)
|
||||
|
||||
However, only do this after a careful study of the density matrix and the dos in the wannier basis.
|
||||
However, do this only after a careful study of the density matrix and
|
||||
the projected DOS in the localized basis.
|
||||
|
||||
A general H(k)
|
||||
--------------
|
||||
|
||||
Loading…
Reference in New Issue
Block a user