Database¶
WfBase computer package includes a database of the density functional theory (DFT) calculations on some simple solids.
Here are three approaches to accessing the database. In each of these three approaches, you should get in the end a folder with the name data containing several files with the .wf extension. Each of these .wf files corresponds to one density functional theory (DFT) calculation.
Following this link you can download the entire database from your browser
or you can get the same file using wget in the terminal (if you have wget installed on your machine):
wget https://coh.ucr.edu/wfbase/latest/data.zip
After downloading this file you should unzip it using a command such as:
unzip data.zip
Alternatively, you can download the same data directly from your python script using the function
download_data_if_needed,import wfbase as wf wf.download_data_if_needed()
The third option to get the database is to first install WfBase and then run the following command from your terminal:
python -c "import wfbase as wf; wf.download_data_if_needed()"
Database entries, which are files with extension .wf in folder data, contain a nearly complete description of the first-principles electronic band structure. Due to the exponential localization of the Wannier functions, and symmetry capabilities implemented in the Wannier Berri package, these files are relatively small in size.
Other materials¶
At this point, WfBase has a rather small set of materials in its database. If you wish to study material that is currently not in the database, you will have to run the density-functional theory (DFT) calculations on your own. The example here provides input files for one of the entries in the database. Your material will likely need a different set of parameters. Once you run your DFT calculation and obtain the needed output files, you can see the following example of how to load that calculation into WfBase.
Information¶
Database file with extension .wf contains results of the DFT calculations. Information about these calculations can be accessed using the info function. Below is an example code that uses the info function to access information about the database.
# Copyright under GNU General Public License 2024
# by Sinisa Coh (see gpl-wfbase.txt)
import wfbase as wf
db = wf.load("data/au_fcc.wf")
db.info()
Below is the output generated by the python code above.
================================
Database file *data/au_fcc.wf*
================================
:The version of this database file:
2024_03_22
:Created using WfBase version:
0.0.2
:Currently loaded WfBase version by this script:
0.0.2
:Created using Wannier Berri version:
0.15.0
:Currently loaded Wannier Berri version:
0.15.0
:Input file for the SCF computation using pw.x from Quantum ESPRESSO:
##################################################################
&control
calculation = 'scf'
restart_mode = 'from_scratch'
pseudo_dir = '.'
outdir = '_work'
prefix = 'pref'
tstress = .true.
tprnfor = .true.
/
&system
ibrav = 0
celldm(1) = 1.0
nat = 1
ntyp = 1
ecutwfc = 75.0
noncolin = .true.
lspinorb = .true.
occupations = 'smearing'
smearing = 'cold'
degauss = 0.03
starting_magnetization(1) = 0
/
&electrons
conv_thr = 1.0e-12
/
ATOMIC_SPECIES
Au 1.0 Au.upf
ATOMIC_POSITIONS crystal
Au 0.0000000000 0.0000000000 0.0000000000
CELL_PARAMETERS alat
-3.9246034918 -0.0000000000 3.9246034918
0.0000000000 3.9246034918 3.9246034918
-3.9246034918 3.9246034918 0.0000000000
K_POINTS automatic
14 14 14 0 0 0
##################################################################
:Input file for the NSCF computation using pw.x from Quantum ESPRESSO:
#######################################################################################
&control
calculation = 'nscf'
restart_mode = 'from_scratch'
pseudo_dir = '.'
outdir = '_work'
prefix = 'pref'
tstress = .true.
tprnfor = .true.
wf_collect = .true.
verbosity = 'high'
/
&system
ibrav = 0
celldm(1) = 1.0
nat = 1
ntyp = 1
ecutwfc = 75.0
nbnd = 69
noncolin = .true.
lspinorb = .true.
occupations = 'smearing'
smearing = 'cold'
degauss = 0.03
starting_magnetization(1) = 0
nosym = .true.
/
&electrons
conv_thr = 1.0e-10
diago_full_acc = .true.
diago_thr_init = 1.0d-10
diagonalization = 'david'
/
ATOMIC_SPECIES
Au 1.0 Au.upf
ATOMIC_POSITIONS crystal
Au 0.0000000000 0.0000000000 0.0000000000
CELL_PARAMETERS alat
-3.9246034918 -0.0000000000 3.9246034918
0.0000000000 3.9246034918 3.9246034918
-3.9246034918 3.9246034918 0.0000000000
K_POINTS crystal
512
0.0000000000 0.0000000000 0.0000000000 0.0019531250
0.0000000000 0.0000000000 0.1250000000 0.0019531250
0.0000000000 0.0000000000 0.2500000000 0.0019531250
0.0000000000 0.0000000000 0.3750000000 0.0019531250
0.0000000000 0.0000000000 0.5000000000 0.0019531250
0.0000000000 0.0000000000 0.6250000000 0.0019531250
0.0000000000 0.0000000000 0.7500000000 0.0019531250
0.0000000000 0.0000000000 0.8750000000 0.0019531250
... cutting long output ... set parameter "full" to True to get complete output.
#######################################################################################
:Pseudopotentials used in the calculation:
https://coh.ucr.edu/wfbase/2024_03_22/psp/Au.upf
:Input file for pw2wannier90.x from Quantum ESPRESSO:
#############################
&inputpp
outdir = '_work'
prefix = 'pref'
seedname = 'x'
write_mmn = .true.
write_amn = .true.
write_spn = .true.
write_unk = .false.
write_uHu = .false.
/
#############################
:Input file for Wannier90:
#######################################################################################
num_bands = 69
num_wann = 18
dis_win_min = 4.41
dis_win_max = 74.09
dis_froz_min = 4.41
dis_froz_max = 30.37
dis_num_iter = 3000
num_iter = 0
spinors = T
begin projections
Au:sp3d2;dxz;dyz;dxy
end projections
write_hr = true
begin unit_cell_cart
bohr
-3.9246034918 -0.0000000000 3.9246034918
0.0000000000 3.9246034918 3.9246034918
-3.9246034918 3.9246034918 0.0000000000
end unit_cell_cart
begin atoms_frac
Au 0.0000000000 0.0000000000 0.0000000000
end atoms_frac
mp_grid = 8 8 8
begin kpoints
0.0000000000 0.0000000000 0.0000000000
0.0000000000 0.0000000000 0.1250000000
0.0000000000 0.0000000000 0.2500000000
0.0000000000 0.0000000000 0.3750000000
0.0000000000 0.0000000000 0.5000000000
0.0000000000 0.0000000000 0.6250000000
0.0000000000 0.0000000000 0.7500000000
0.0000000000 0.0000000000 0.8750000000
0.0000000000 0.1250000000 0.0000000000
0.0000000000 0.1250000000 0.1250000000
0.0000000000 0.1250000000 0.2500000000
0.0000000000 0.1250000000 0.3750000000
0.0000000000 0.1250000000 0.5000000000
0.0000000000 0.1250000000 0.6250000000
0.0000000000 0.1250000000 0.7500000000
0.0000000000 0.1250000000 0.8750000000
0.0000000000 0.2500000000 0.0000000000
0.0000000000 0.2500000000 0.1250000000
0.0000000000 0.2500000000 0.2500000000
... cutting long output ... set parameter "full" to True to get complete output.
#######################################################################################
