mirror of
https://github.com/triqs/dft_tools
synced 2024-12-22 20:34:38 +01:00
135 lines
11 KiB
ReStructuredText
135 lines
11 KiB
ReStructuredText
.. _hdfstructure:
|
|
|
|
hdf5 structure
|
|
==============
|
|
|
|
All the data is stored using the hdf5 standard, as described also in the
|
|
documentation of the TRIQS package itself. In order to do a DMFT calculation,
|
|
using input from DFT applications, a converter is needed on order to provide
|
|
the necessary data in the hdf5 format.
|
|
|
|
groups and their formats
|
|
------------------------
|
|
|
|
In order to be used with the DMFT routines, the following data needs to be
|
|
provided in the hdf5 file. It contains a lot of information in order to perform
|
|
DMFT calculations for all kinds of situations, e.g. d-p Hamiltonians, more than
|
|
one correlated atomic shell, or using symmetry operations for the k-summation.
|
|
We store all data in subgroups of the hdf5 archive:
|
|
|
|
Main data
|
|
^^^^^^^^^
|
|
There needs to be one subgroup for the main data of the
|
|
calculation. The default name of this group is `dft_input`. Its contents are
|
|
|
|
================= ====================================================================== =====================================================================================
|
|
Name Type Meaning
|
|
================= ====================================================================== =====================================================================================
|
|
energy_unit numpy.float Unit of energy used for the calculation.
|
|
n_k numpy.int Number of k-points used for the BZ integration.
|
|
k_dep_projection numpy.int 1 if the dimension of the projection operators depend on the k-point,
|
|
0 otherwise.
|
|
SP numpy.int 1 for spin-polarised Hamiltonian, 0 for paramagnetic Hamiltonian.
|
|
SO numpy.int 1 if spin-orbit interaction is included, 0 otherwise.
|
|
charge_below numpy.float Number of electrons in the crystal below the correlated orbitals.
|
|
Note that this is for compatibility with dmftproj.
|
|
density_required numpy.float Required total electron density. Needed to determine the chemical potential.
|
|
The density in the projection window is then `density_required`-`charge_below`.
|
|
symm_op numpy.int 1 if symmetry operations are used for the BZ sums,
|
|
0 if all k-points are directly included in the input.
|
|
n_shells numpy.int Number of atomic shells for which post-processing is possible.
|
|
Note: this is `not` the number of correlated orbitals!
|
|
If there are two equivalent atoms in the unit cell, `n_shells` is 2.
|
|
shells list of dict {string:int}, dim n_shells x 4 Atomic shell information.
|
|
For each shell, have a dict with keys ['atom', 'sort', 'l', 'dim'].
|
|
'atom' is the atom index, 'sort' defines the equivalency of the atoms,
|
|
'l' is the angular quantum number, 'dim' is the dimension of the atomic shell.
|
|
e.g. for two equivalent atoms in the unit cell, `atom` runs from 0 to 1,
|
|
but `sort` can take only one value 0.
|
|
n_corr_shells numpy.int Number of correlated atomic shells.
|
|
If there are two correlated equivalent atoms in the unit cell, `n_corr_shells` is 2.
|
|
corr_shells list of dict {string:int}, dim n_corr_shells x 6 Correlated orbital information.
|
|
For each correlated shell, have a dict with keys
|
|
['atom', 'sort', 'l', 'dim', 'SO', 'irep'].
|
|
'atom' is the atom index, 'sort' defines the equivalency of the atoms,
|
|
'l' is the angular quantum number, 'dim' is the dimension of the atomic shell.
|
|
'SO' is one if spin-orbit is included, 0 otherwise, 'irep' is a dummy integer 0.
|
|
use_rotations numpy.int 1 if local and global coordinate systems are used, 0 otherwise.
|
|
rot_mat list of numpy.array.complex, Rotation matrices for correlated shells, if `use_rotations`.
|
|
dim n_corr_shells x [corr_shells['dim'],corr_shells['dim']] Set to the unity matrix if no rotations are used.
|
|
rot_mat_time_inv list of numpy.int, dim n_corr_shells If `SP` is 1, 1 if the coordinate transformation contains inversion, 0 otherwise.
|
|
If `use_rotations` or `SP` is 0, give a list of zeros.
|
|
n_reps numpy.int Number of irreducible representations of the correlated shell.
|
|
e.g. 2 if eg/t2g splitting is used.
|
|
dim_reps list of numpy.int, dim n_reps Dimension of the representations.
|
|
e.g. [2,3] for eg/t2g subsets.
|
|
T list of numpy.array.complex, Transformation matrix from the spherical harmonics to impurity problem basis
|
|
dim n_inequiv_corr_shell x normally the real cubic harmonics).
|
|
[max(corr_shell['dim']),max(corr_shell['dim'])] This matrix is used to calculate the 4-index U matrix.
|
|
n_orbitals numpy.array.int, dim [n_k,SP+1-SO] Number of Bloch bands included in the projection window for each k-point.
|
|
If SP+1-SO=2, the number of included bands may depend on the spin projection up/down.
|
|
proj_mat numpy.array.complex, Projection matrices from Bloch bands to Wannier orbitals.
|
|
dim [n_k,SP+1-SO,n_corr_shells,max(corr_shell['dim']),max(n_orbitals)] For efficient storage reasons, all matrices must be of the same size
|
|
(given by last two indices).
|
|
For k-points with fewer bands, only the first entries are used, the rest are zero.
|
|
e.g. if number of Bloch bands ranges from 4-6, all matrices are of size 6.
|
|
bz_weights numpy.array.float, dim n_k Weights of the k-points for the k summation.
|
|
hopping numpy.array.complex, Non-interacting Hamiltonian matrix for each k point.
|
|
dim [n_k,SP+1-SO,max(n_orbitals),max(n_orbitals)] As for `proj_mat`, all matrices have to be of the same size.
|
|
================= ====================================================================== =====================================================================================
|
|
|
|
|
|
Symmetry operations
|
|
^^^^^^^^^^^^^^^^^^^
|
|
In this subgroup we store all the data for applying the symmetry operations in
|
|
the DMFT loop (in case you want to use symmetry operations). The default name
|
|
of this subgroup is `dft_symmcorr_input`. This information is needed only if symmetry
|
|
operations are used to do the k summation. To be continued...
|
|
|
|
.. warning::
|
|
TO BE COMPLETED!
|
|
|
|
General and simple H(k) Converter
|
|
---------------------------------
|
|
|
|
The above described converter of the Wien2k input is quite involved, since
|
|
Wien2k provides a lot of information, e.g. about symmetry operations, that can
|
|
be used in the calculation. However, sometimes we want to use a light
|
|
implementation where the input consists basically only of the Hamiltonian
|
|
matrix in Wannier basis, given at a grid of k points in the first Brillouin
|
|
zone. For this purpose, a simple converter is included in the package, called
|
|
:class:`HkConverter`, which is implemented for the simplest case of
|
|
paramagnetic DFT calculations without spin-orbit coupling. It reads a simple,
|
|
easy to construct text file, and produces an archive that can be used for the
|
|
DMFT calculations. An example input file for a structure with one correlated
|
|
site with 3 t2g orbitals in the unit cell contains the following:
|
|
|
|
10 <- n_k
|
|
|
|
1.0 <- density_required
|
|
|
|
1 <- n_shells
|
|
|
|
1 1 2 3 <- shells, as above: atom, sort, l, dim
|
|
|
|
1 <- n_corr_shells
|
|
|
|
1 1 2 3 0 0 <- corr_shells, as above: atom, sort, l, dim, SO, dummy
|
|
|
|
2 2 3 <- n_reps, dim_reps (length 2, because eg/t2g splitting) for each inequivalent correlated shell
|
|
|
|
After this header, we give the Hamiltonian matrices for al the k-points. for
|
|
each k-point we give first the matrix of the real part, then the matrix of the
|
|
imaginary part. The projection matrices are set automatically to unity
|
|
matrices, no rotations, no symmetry operations are used. That means that the
|
|
symmetry sub group in the hdf5 archive needs not be set, since it is not used.
|
|
It is furthermore assumed that all k-points have equal weight in the k-sum.
|
|
Note that the input file should contain only the numbers, not the comments
|
|
given in above example.
|
|
|
|
The Hamiltonian matrices can be taken, e.g., from Wannier90, which contructs
|
|
the Hamiltonian in a maximally localised Wannier basis.
|
|
|
|
Note that with this simplified converter, no full charge self consistent
|
|
calculations are possible!
|