Running a Wannier90 minimal workchain¶
GaAs wannierization workchain¶
This AiiDA workchain runs a full workflow from scratch (i.e., both Quantum ESPRESSO and Wannier90) to wannierise a GaAs crystal using manually-specified projections. The workflow returns the parsed information from the standard Wannier90 output (i.e. centres, spreads, etc.) and the interpolated band structure.
We use in the following the
verdi command-line interface (CLI).
A reminder of a few useful AiiDA commands:
verdi process list -a -p <N>(to monitor the state of the calculations done in the last
verdi process show <identifier>(to list inputs and outputs of a calculation, especially useful after the calculation is finished)
Run your simulation¶
Open a terminal and enter the virtual environment where AiiDA is installed.
Then, enter the
examples/workflows folder of the
plugin and run the following script to launch a new workflow:
This will show the help of the command. You need to specify three
required parameters: a
quantumespresso.pw code, a
quantumespresso.pw2wannier90 code and a
(that you need to setup before). An example full command looks like:
./launch_w90_minimal.py -s pw@computer -p pw2wannier90@computer -w wannier90@computer
This will launch the simple workchain that is provided with
aiida-wannier90, whose class name is
that is found in the python module
Note: in this example we use sp3 orbitals centred on As atoms as starting guesses for projections. For more details about the inputs of QE and Wannier90 calculations you can inspect both the launcher and the workchain itself.
Check the results¶
When you run the
launch_w90_minimal.py, on screen you will get an
output line for each step running (i.e. in order:
wannier90.x run), reporting the identifier (PK) of each calculation.
You can inspect each calculation node by typing, for instance:
verdi process show <PK>
to see the inputs and outputs of each calculation, or
verdi data dict show <PK>
to inspect the contect of
Dict nodes, such as the
output_parameters of the Wannier90 calculation, containing the
parsed information from the output of the code.
As final results you get all the information parsed in AiiDA and saved as outputs, as documented in the previous sections.
Once the calculation is finished, you export or visualize the resulting
bands interpolated using maximally-localised Wannier functions (MLWFs).
First, find the PK of the
BandStructure returned by the workflow
using the command:
verdi node show <PK>
(passing the workflow PK). The
BandStructure PK is found by looking
for the output node with link label
BandStructure PK, you can show the bands with xmgrace
verdi data bands show -F agr <PK>
or export it to file using:
verdi data bands export -F agr <PK> -o interpolated.agr
interpolated.agr is the output file name where the band
structure will be stored.
Compare with DFT bands¶
You can compare the interpolated band structure with the bands obtained
directly from DFT (Quantum ESPRESSO). You can compute this band
structure, but for convenience we provide the
DFT-bands.agr file in
the same folder. After having exported the MLWF-interpolated bands as
explained above, you can plot together both of them, executing the
xmgrace DFT-bands.agr interpolated.agr
You should see something like the following plot (where we just changed some graphical aspects):
Visualizing AiiDA provenance graphs¶
verdi node graph generate <PK>
where you can use the PK of a node for which you want to see the provenance (for instance a calculation, or the final band structure).
This command, by default, generates a PDF file named
that you can view with your favourite software.