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Added docs on PLOVasp

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Added description of the input file and a general section
on the interface.
Also, an example input file for SrVO3 is added.
This commit is contained in:
Oleg E. Peil 2016-12-31 11:12:16 +01:00
parent 6b89a0a6f0
commit 54022c3952
3 changed files with 159 additions and 3 deletions
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64
doc/guide/conversion.rst
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@ -181,7 +181,71 @@ since we need also the :program:`optics` package of Wien2k. Please
look at the section on :ref:`Transport` to see how to do the necessary
steps, including the conversion.
Interface with VASP
---------------------
The interface with VASP relies on new options introduced since
version 5.4.x. The output of raw (non-normalized) projectors is
controlled by an INCAR option LOCPROJ whose complete syntax is described in
VASP documentaion.
The definition of a projector set starts with specifying which sites
and which local states we are going to projecto onto.
This information is provided using option LOCPROJ
| `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.);
`<projector type>` chooses a particular type of the local basis function.
Some projector types also require parameters `EMIN`, `EMAX` in INCAR to
be set to define an (approximate) energy window corresponding to the
valence states.
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.
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 processing of projectors is performed by the program :program:`plovasp`
invoked as
| `plovasp <plo.cfg>`
where `<plo.cfg>` is a input file controlling the conversion of projectors.
The format of input file `<plo.cfg>` is described in details in
:ref:`plovasp`. Here we just give a simple example for the case
of SrVO3:
.. literalinclude:: images_scripts/srvo3.cfg
A projector shell is defined by a section `[Shell 1]` where the number
can be arbitrary and used only for user convenience. Several
parameters are required
- **IONS**: list of site indices which must be a subset of indices
given earlier in `LOCPROJ`.
- **LSHELL**: :math:`l`-quantum number of the projector shell; the corresponding
orbitals must be present in `LOCPROJ`.
- **EWINDOW**: energy window in which the projectors are normalized;
note that the energies are defined with respect to the Fermi level.
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`.
A general H(k)
--------------

8
doc/guide/images_scripts/srvo3.cfg Normal file
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@ -0,0 +1,8 @@
[Shell 1]
LSHELL = 2
IONS = 2
EWINDOW = -1.45 1.8
TRANSFORM = 1.0 0.0 0.0 0.0 0.0
0.0 1.0 0.0 0.0 0.0
0.0 0.0 0.0 1.0 0.0

90
doc/guide/plovasp.rst
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@ -25,7 +25,7 @@ raw projectors. Note, however, that DFTtools does not support projector
groups at the moment but this feature might appear in future releases.
A set of projectors defined on sites realted to each other either by symmetry
or by sort along with a set of `l`, `m` quantum numbers forms a
or by sort along with a set of :math:`l`, :math:`m` quantum numbers forms a
`projector shell`. There could be several projectors shells in a
projector group, implying that they will be normalized within
the same energy window.
@ -45,13 +45,97 @@ A PLOVasp input file can contain three types of sections:
#. **[General]**: includes parameters that are independent
of a particular projector set, such as the Fermi level, additional
output (e.g. the density of states), etc.
#. **[Group <Ng>]**: describes projector groups, i.e. a set of
projectors sharing the same energy window and normalization type.
At the moment, DFTtools support only one projector group, therefore
there should be no more than one projector group.
#. **[Shell <Ns>]**: contains parameters of a projector shell labelled
with `<Ns>`. If there is only one group section and one shell section,
the group section can be omitted and its required parameters can be
given inside the single shell section.
Section [General]
"""""""""""""""""
The entire section is optional and it contains three parameters:
* **BASENAME** (string): provides a base name for output files.
Default filenames are :file:`vasp.*`.
* **DOSMESH** ([float float] integer): if this parameter is given
projected density of states for each projected orbital will be
evaluated and stored to files :file:`pdos_<n>.dat`, where `n` is the
orbital number. The energy
mesh is defined by three numbers: `EMIN` `EMAX` `NPOINTS`. The first two
can be omitted in which case they are taken to be equal to the projector
energy window. **Important note**: at the moment this option works
only if the tetrahedron integration method (`ISMEAR = -4` or `-5`)
is used in VASP to produce `LOCPROJ`.
* **EFERMI** (float): provides the Fermi level. This value overrides
the one extracted from VASP output files.
There are no required parameters in this section.
Section [Shell]
"""""""""""""""
This section specifies a projector shell. Each shell section must be
labeled by an index, e.g. `[Shell 1]`. These indices can then be referenced
in a `[Group]` section.
In each `[Shell]` section two parameters are required:
* **IONS** (list of integer): indices of sites included in the shell.
The sites can be given either by a list of integers `IONS = 5 6 7 8`
or by a range `IONS = 5..8`. The site indices must be compatible with
POSCAR file.
* **LSHELL** (integer): :math:`l` quantum number of the desired local states.
It is important that a given combination of site indices and local states
given by `LSHELL` must be present in LOCPROJ file.
There are additional optional parameters that allow one to transform
the local states:
* **TRANSFORM** (matrix): local transformation matrix applied to all states
in the projector shell. The matrix is defined by (multiline) block
of floats, with each line corresponding to a row. The number of columns
must be equal to :math:`2 l + 1`, with :math:`l` given by `LSHELL`. Only real matrices
are allowed. This parameter can be useful to select certain subset of
orbitals or perform a simple global rotation.
* **TRANSFILE** (string): name of the file containing transformation
matrices for each site. This option allows for a full-fledged functionality
when it comes to local state transformations. The format of this file
is described in :ref:`_transformation_file`.
Section [Group]
"""""""""""""""
Each defined projector shell must be part of a projector group. In the current
implementation of DFTtools only a single group is supported which can be
labeled by any integer, e.g. `[Group 1]`. This implies that all projector shells
must be included in this group.
Required parameters for any group are the following:
* **SHELLS** (list of integers): indices of projector shells included in the group.
All defined shells must be grouped.
* **EWINDOW** (float float): the energy window specified by two floats: bottom
and top. All projectors in the current group are going to be normalized within
this window.
Optional group parameters:
* **NORMALIZE** (True/False): specifies whether projectors in the group are
to be noramlized. The default value is **True**.
* **NORMION** (True/False): specifies whether projectors are normalized on
a per-site (per-ion) basis. That is, if `NORMION = True` the orthogonality
condition will be enforced on each site separately but the Wannier functions
on different sites will not be orthogonal. If `NORMION = False` Wannier functions
on different sites included in the group will be orthogonal to each other.
.. _transformation_file
File of transformation matrices
"""""""""""""""""""""""""""""""