[gpaw-users] Band structure calculation

[Jens Jørgen Mortensen]

On 01-02-2012 11:21, Jakob Arendt Rasmussen wrote:
> Hi
>
> I'm doing a band structure  calculation along the second axis in the
> brillouin zone where I do one k-point at a time. this works fine in
> fd-mode, but in lcao-mode I get weird (i.e. large (numerically))
> eigenvalues for the gamma-point - giving an ugly spaghetti-plot... The
> eigenvalues for the gamma-point spans from -520000 eV to -120 eV jumping
> tens of eV in the valence end whereas for the other k-points the
> eigenvalues spans from -22 eV to 1.8 eV jumping tens of meV.

Can you send us the 3x9_con.traj file?  On how many cores do you run the 
bandstructure calculation?

Jens Jørgen

> The structure optimization was done like this:
> ###########################
> from ase.io.trajectory import PickleTrajectory
> from ase.optimize import BFGS
> from gpaw import GPAW
>
> id='3x9_con'
> traj=PickleTrajectory(id+'.traj')
> atoms=traj[-1]
>
> calc=GPAW(nbands=170,
>             mode='lcao',
>             basis='dzp',
>             h=0.16,
>             kpts=(1,8,1),
>             xc='PBE',
>             spinpol=True,
>             txt=id+'_opt.txt')
>
> atoms.set_calculator(calc)
> dyn=BFGS(atoms,trajectory=id+'_opt.traj',logfile=id+'_opt.log')
> dyn.run(fmax=0.05)
> calc.write(id+'_opt.gpw')
> ###########################
>
> and the band structure like this:
> ###########################
> from gpaw import GPAW
> from gpaw.mixer import MixerSum
> import os
>
> id='3x9_con'
>
> nkpt = 40
> kpts = [(0, 0.5 * k / (nkpt - 1), 0) for k in range(nkpt)]
>
> for kpt in kpts:
>       if id+'_%1.2f_band.gpw' %kpt[1] in os.listdir('./'):
>           continue
>       else:
>           calc = GPAW(id+'_opt.gpw',
>                       txt=id+'_%1.2f_band.txt' %kpt[1],
>                       kpts=[kpt],
>                       fixdensity=True,
>                       usesymm=None,
>                       maxiter=500,
>                       mixer=MixerSum(),
>                       convergence={'bands': -5})
>
>           calc.scf.converged=False
>
>           calc.get_potential_energy()
>           calc.write(id+'_%1.2f_band.gpw' %kpt[1])
> ###########################
>
> Best,
> Jakob
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