bands_Si.py

from ase.build.bulk import bulk
from ase.calculators.vasp import Vasp
from ase.io import read
from ase.dft.band_structure import BandStructure

si = bulk('Si', 'diamond', a=5.4)
si.calc = Vasp(kpts=(4, 4, 4), xc='PBE')
si.get_potential_energy()

si.calc.set(icharg=11, # Read charge density from CHGCAR
            kpts={'path': 'WLGXWK', 'npoints': 100},
            isym=0)

si.get_potential_energy()

bs = BandStructure(read('vasprun.xml'))
bs.plot(emax=5.0, filename='bands_Si.pdf')