Bugfix: Store band structure efermi in CalculationOutput

[Andrew-S-Rosen]

This PR stores the efermi from the vasprun.xml band structure in CalculationOutput. Currently, it is always left at None because it wasn't assigned in electronic_output. Small bugfix.

Example:

from atomate2.vasp.schemas.calculation import CalculationOutput
from pymatgen.io.vasp.outputs import Vasprun, Outcar

# run this in, e.g. one of the test double-relax runs
c = CalculationOutput.from_vasp_outputs(Vasprun('vasprun.xml.gz'),Outcar('OUTCAR.gz'))

[codecov-commenter]

Codecov Report

Merging #66 (5d9ef7c) into main (fe5d8a6) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
- Coverage   70.39%   70.38%   -0.02%     
==========================================
  Files          45       45              
  Lines        3804     3809       +5     
  Branches      576      576              
==========================================
+ Hits         2678     2681       +3     
- Misses        979      981       +2     
  Partials      147      147              

Impacted Files	Coverage Δ
src/atomate2/vasp/schemas/calculation.py	83.73% <ø> (ø)
src/atomate2/utils/path.py	88.23% <0.00%> (-11.77%)	⬇️
src/atomate2/vasp/flows/core.py	93.91% <0.00%> (+0.27%)	⬆️

[Andrew-S-Rosen]

On a side-note, in this failed test (where I checked the test_doc.efermi against vasprun.efermi instead of vasprun.get_band_structure(efermi='smart') by accident), the efermi from vasprun.efermi is 6.23352981 eV but from vasprun.get_band_structure(efermi='smart') is 5.9249 eV. Pretty big difference! Is this normal, @utf?

[utf]

Pretty big difference! Is this normal, @utf?

Yes, this is because there's a bug that affects the Fermi level position for VASP 6.1+ with tetrahedron smearing. It is on the VASP wiki here: https://www.vasp.at/forum/viewtopic.php?f=4&t=18201

Thanks for this fix!