mirror of
https://github.com/triqs/dft_tools
synced 2024-09-12 05:38:31 +02:00
Merge pull request #180 from phibeck/w90
- Documentation update of the w90 interface - fix bloch basis version of w90 converter
This commit is contained in:
commit
c0242118b0
@ -1,30 +1,36 @@
|
||||
.. _convW90:
|
||||
|
||||
Wannier90 Converter
|
||||
===================
|
||||
Interface with Wannier90
|
||||
========================
|
||||
|
||||
Using this converter it is possible to convert the output of
|
||||
`wannier90 <http://wannier.org>`_
|
||||
Maximally Localized Wannier Functions (MLWF) and create a HDF5 archive
|
||||
suitable for one-shot DMFT calculations with the
|
||||
:class:`SumkDFT <dft.sumk_dft.SumkDFT>` class.
|
||||
This interface allows to convert the output of `wannier90 <http://wannier.org>`_
|
||||
Maximally Localized Wannier Functions (MLWF) and create a HDF5 archive suitable for DMFT calculations with the
|
||||
:class:`SumkDFT <dft.sumk_dft.SumkDFT>` class. The tasks are parallelized with MPI.
|
||||
|
||||
The user must supply two files in order to run the Wannier90 Converter:
|
||||
The converter can be run in two different modes, which are specified with the keyword ``bloch_basis`` in the call::
|
||||
|
||||
from triqs_dft_tools.converters import Wannier90Converter
|
||||
Converter = Wannier90Converter(seedname='seedname', bloch_basis=False, rot_mat_type='hloc_diag', add_lambda=None)
|
||||
|
||||
Here and in the following, the keyword ``seedname`` should always be intended
|
||||
as a placeholder for the actual prefix chosen by the user when creating the
|
||||
input for :program:`wannier90`.
|
||||
|
||||
Orbital mode
|
||||
---------------
|
||||
|
||||
In the default mode (``bloch_basis = False``), the Converter writes the Hamiltonian in orbital basis, in which case
|
||||
the projector functions are trivial identity matrices. The user must supply two files:
|
||||
|
||||
#. The file :file:`seedname_hr.dat`, which contains the DFT Hamiltonian
|
||||
in the MLWF basis calculated through :program:`wannier90` with ``hr_plot = true``
|
||||
in the MLWF basis calculated through :program:`wannier90` with ``write_hr = true``
|
||||
(please refer to the :program:`wannier90` documentation).
|
||||
#. A file named :file:`seedname.inp`, which contains the required
|
||||
information about the :math:`\mathbf{k}`-point mesh, the electron density,
|
||||
the correlated shell structure, ... (see below).
|
||||
|
||||
Here and in the following, the keyword ``seedname`` should always be intended
|
||||
as a placeholder for the actual prefix chosen by the user when creating the
|
||||
input for :program:`wannier90`.
|
||||
Once these two files are available, one can use the converter as follows::
|
||||
|
||||
from triqs_dft_tools.converters import Wannier90Converter
|
||||
Converter = Wannier90Converter(seedname='seedname')
|
||||
Converter.convert_dft_input()
|
||||
|
||||
The converter input :file:`seedname.inp` is a simple text file with
|
||||
@ -84,15 +90,57 @@ In our `Pnma`-LaVO\ :sub:`3` example, for instance, we could use::
|
||||
where the ``x=-1,1,0`` option indicates that the V--O bonds in the octahedra are
|
||||
rotated by (approximatively) 45 degrees with respect to the axes of the `Pbnm` cell.
|
||||
|
||||
The last line of :file:`seedname.inp` is the DFT Fermi energy (in eV), which is subtracted from the onsite terms in the :file:`seedname_hr.dat` file. This is recommended since some functions in DFTTools implicitly assume a Fermi energy of 0 eV.
|
||||
The last line of :file:`seedname.inp` is the DFT Fermi energy (in eV), which is subtracted from the onsite
|
||||
terms in the :file:`seedname_hr.dat` file. This is recommended since some functions in DFTTools implicitly
|
||||
assume a Fermi energy of 0 eV.
|
||||
|
||||
In the orbital mode the Converter supports the addition of a local spin-orbit term, if the Wannier Hamiltonian
|
||||
describes a t\ :sub:`2g` manifold. Currently, the correct interaction term is only implemented if the default
|
||||
orbital order of :program:`wannier90` is maintained, i.e. it is assumed to be
|
||||
:math:`d_{xz,\uparrow}, d_{yz,\uparrow}, d_{xy,\uparrow}, d_{xz,\downarrow}, d_{yz,\downarrow}, d_{xy,\downarrow}`.
|
||||
The coupling strength can be specified as ``add_lambda = [lambda_x, lambda_y, lambda_z]``,
|
||||
representative of the orbital coupling terms perpendicular to :math:`[x, y, z]` i.e. :math:`[d_{yz}, d_{xz}, d_{xy}]`,
|
||||
respectively. Note that it is required to have ``SO=0`` and ``SP=1``.
|
||||
|
||||
Band mode
|
||||
----------------
|
||||
|
||||
If ``bloch_basis = True``, the Converter writes the Hamiltonian in the Kohn-Sham basis that was used to construct
|
||||
the Wannier functions. The projector functions are then given by the transformation from Kohn-Sham to orbital basis.
|
||||
Note that to do so :program:`wannier90` must be run with ``write_u_matrices = true``. Additionally to the files
|
||||
described above, the Converter will require the following files:
|
||||
|
||||
#. :file:`seedname_u.mat` (and :file:`seedname_u_dis.mat` if disentanglement was used to construct the Wannier functions.) is read to construct the projector functions.
|
||||
#. :file:`seedname.eig` is read to get the Kohn-Sham band eigenvalues
|
||||
#. :file:`seedname.nnkp` is read to obtain the band indices of the orbitals selected for the Wannier Hamiltonian
|
||||
#. :file:`seedname.wout` is read to get the outer energy window to ensure the correct mapping of the disentanglement
|
||||
|
||||
Note that in case of disentanglement the user must set the outer energy window (``dis_win_min`` and ``dis_win_max``) explicitly in :program:`wannier90` with an energy
|
||||
separation of at least :math:`10^{-4}` to the band energies. This means in particular that one should not use the default energy window to avoid subtle bugs.
|
||||
|
||||
Additionally, to keep the dimension of the lattice Green's function reasonable, it is recommendable to use the exclude_bands tag for bands completely outside of the energy window.
|
||||
|
||||
The Converter currently works with Quantum Espresso and VASP. Additional files are required for each case to obtain
|
||||
the Fermi weights:
|
||||
|
||||
#. :file:`seedname.nscf.out` for Quantum Espresso (the NSCF run must contain the flag ``verbosity = 'high'``)
|
||||
#. :file:`OUTCAR` and :file:`LOCPROJ` for VASP
|
||||
|
||||
Note that in the band mode the user input of the :math:`k`-mesh and the Fermi energy in :file:`seedname.inp` are ignored, since both quantities
|
||||
are automatically read from the :program:`wannier90` and DFT output. However, the :math:`k`-mesh parameter still has to be specified to comply with the file format.
|
||||
|
||||
Rotation matrix
|
||||
------------------
|
||||
|
||||
The converter will analyse the matrix elements of the local Hamiltonian
|
||||
to find the symmetry matrices `rot_mat` needed for the global-to-local
|
||||
transformation of the basis set for correlated orbitals
|
||||
(see section :ref:`hdfstructure`).
|
||||
The matrices are obtained by finding the unitary transformations that diagonalize
|
||||
If ``rot_mat_type='hloc_diag'``, the matrices are obtained by finding the unitary transformations that diagonalize
|
||||
:math:`\langle w_i | H_I(\mathbf{R}=0,0,0) | w_j \rangle`, where :math:`I` runs
|
||||
over the correlated shells and `i,j` belong to the same shell (more details elsewhere...).
|
||||
If ``rot_mat_type='wannier'``, the matrix for the first correlated shell per impurity will be identity, defining the reference frame,
|
||||
while the rotation matrices of all other equivalent shells contain the correct mapping into this reference frame.
|
||||
If two correlated shells are defined as equivalent in :file:`seedname.inp`,
|
||||
then the corresponding eigenvalues have to match within a threshold of 10\ :sup:`-5`,
|
||||
otherwise the converter will produce an error/warning.
|
||||
@ -100,20 +148,17 @@ If this happens, please carefully check your data in :file:`seedname_hr.dat`.
|
||||
This method might fail in non-trivial cases (i.e., more than one correlated
|
||||
shell is present) when there are some degenerate eigenvalues:
|
||||
so far tests have not shown any issue, but one must be careful in those cases
|
||||
(the converter will print a warning message).
|
||||
(the converter will print a warning message and turns off the use of rotation matrices,
|
||||
which leads to an incorrect mapping between equivalent correlated shells).
|
||||
|
||||
Current limitations
|
||||
----------------------------------------------
|
||||
|
||||
The current implementation of the Wannier90 Converter has some limitations:
|
||||
|
||||
* Since :program:`wannier90` does not make use of symmetries (symmetry-reduction
|
||||
of the :math:`\mathbf{k}`-point grid is not possible), the converter always
|
||||
sets ``symm_op=0`` (see the :ref:`hdfstructure` section).
|
||||
* No charge self-consistency possible at the moment.
|
||||
* Calculations with spin-orbit (``SO=1``) are not supported.
|
||||
* The spin-polarized case (``SP=1``) is not yet tested.
|
||||
* The post-processing routines in the module
|
||||
:class:`SumkDFTTools <dft.sumk_dft_tools.SumkDFTTools>`
|
||||
were not tested with this converter.
|
||||
* ``proj_mat_all`` are not used, so there are no projectors onto the
|
||||
uncorrelated orbitals for now.
|
||||
|
||||
|
||||
|
@ -41,6 +41,8 @@
|
||||
# this might fail in presence of degenerate eigenvalues (now just prints warning)
|
||||
# - make the code more MPI safe (error handling): if we run with more than one process
|
||||
# and an error occurs on the masternode, the calculation does not abort
|
||||
# - in case of disentanglement, the outer window being close to Kohn-Sham energies
|
||||
# can cause a problem in creating the udis_mat in read_wannier90data
|
||||
###
|
||||
|
||||
|
||||
@ -456,8 +458,16 @@ class Wannier90Converter(ConverterTools):
|
||||
# corresponds to W90 result
|
||||
wannier_ham = self.fourier_ham(hamr_full[isp])
|
||||
for ik in range(self.n_k):
|
||||
proj_mat_flattened = proj_mat[ik, isp].reshape(self.nwfs, numpy.max(n_orbitals))
|
||||
proj_mat_flattened = numpy.zeros((numpy.max(n_orbitals), numpy.max(n_orbitals)), dtype=complex)
|
||||
iorb = 0
|
||||
for icrsh in range(n_corr_shells):
|
||||
dim = corr_shells[icrsh]['dim']
|
||||
proj_mat_flattened[iorb:iorb+dim,:] = proj_mat[ik, isp][icrsh,0:dim,:].reshape(dim, numpy.max(n_orbitals))
|
||||
iorb += dim
|
||||
downfolded_ham = proj_mat_flattened.dot(hamk[ik].dot(proj_mat_flattened.conj().T))
|
||||
if dim_corr_shells < numpy.max(n_orbitals):
|
||||
downfolded_ham = downfolded_ham[:dim_corr_shells,:dim_corr_shells]
|
||||
wannier_ham[ik] = wannier_ham[ik][:dim_corr_shells,:dim_corr_shells]
|
||||
|
||||
if not numpy.allclose(downfolded_ham, wannier_ham[ik], atol=1e-4, rtol=0):
|
||||
mpi.report('WARNING: mismatch between downfolded Hamiltonian and '
|
||||
|
Loading…
Reference in New Issue
Block a user