ASE Manual Release 3.6.1.2825 CAMd - CampOS Wiki

ASE Manual, Release 3.6.1.2828
kpts = monkhorst_pack((13, 1, 1)) + [1e-5, 0, 0]
calc = GPAW(h=.21, xc=’PBE’, kpts=kpts, nbands=12, txt=’poly.txt’,
eigensolver=’cg’, convergence={’bands’: 9})
CC = 1.38
CH = 1.094
a = 2.45
x = a / 2.
y = np.sqrt(CC**2 - x**2)
atoms = Atoms(’C2H2’, pbc=(True, False, False), cell=(a, 8., 6.),
calculator=calc, positions=[[0, 0, 0],
[x, y, 0],
[x, y+CH, 0],
[0, -CH, 0]])
atoms.center()
atoms.get_potential_energy()
calc.write(’poly.gpw’, mode=’all’)
import numpy as np
from ase.dft import Wannier
from gpaw import restart
atoms, calc = restart(’poly.gpw’, txt=None)
# Make wannier functions using (one) extra degree of freedom
wan = Wannier(nwannier=6, calc=calc, fixedenergy=1.5)
wan.localize()
wan.save(’poly.pickle’)
wan.translate_all_to_cell((2, 0, 0))
for i in range(wan.nwannier):
wan.write_cube(i, ’polyacetylene_%i.cube’ % i)
# Print Kohn-Sham bandstructure
ef = calc.get_fermi_level()
f = open(’KSbands.txt’, ’w’)
for k, kpt_c in enumerate(calc.get_ibz_k_points()):
for eps in calc.get_eigenvalues(kpt=k):
print >> f, kpt_c[0], eps - ef
# Print Wannier bandstructure
f = open(’WANbands.txt’, ’w’)
for k in np.linspace(-.5, .5, 100):
for eps in np.linalg.eigvalsh(wan.get_hamiltonian_kpoint([k, 0, 0])).real:
print >> f, k, eps - ef
import pylab as pl
fig = pl.figure(1, dpi=80, figsize=(4.2, 6))
fig.subplots_adjust(left=.16, right=.97, top=.97, bottom=.05)
# Plot KS bands
k, eps = pl.load(’KSbands.txt’, unpack=True)
pl.plot(k, eps, ’ro’, label=’DFT’, ms=9)
# Plot Wannier bands
k, eps = pl.load(’WANbands.txt’, unpack=True)
pl.plot(k, eps, ’k.’, label=’Wannier’)
pl.plot([-.5, .5], [1, 1], ’k:’, label=’_nolegend_’)
pl.text(-.5, 1, ’fixedenergy’, ha=’left’, va=’bottom’)
pl.axis(’tight’)
pl.xticks([-.5, -.25, 0, .25, .5],
44 Chapter 6. Tutorials