[gpaw-users] Cu2O dipole corrections - convergence problems

[ZhenHua Zeng]

Hi Isabela,

When you did not apply dipole correction, the calculations were 
convergent, but seem not fine at all, i.e. there is a band gap around 
300 eV in empty band.
I think you need to fix out this problem firstly. Does anyone know the 
reason for this 'huge' band gap?

Regards,
Zhenhua

Isabela Man wrote:
> Dear all,
> I am trying to do some calculations on different Cu2O surfaces (100, 
> 110, 111 surfaces and for each different surface terminations).
> For all cases I encounter the same problem. When I do not apply dipole 
> corrections , everything is fine and I get the convergence. When I 
> apply it, depending on surface after none, one or two steps the energy 
> become positive.
>
> mixer=Mixer(0.1, 5, weight=100.0)
> calc = GPAW(h=0.2,
> xc='RPBE',
> txt=outid,
> kpts=(2,2,1),
> #eigensolver='cg',
> width=0.10,
> #verbose=True,
> mixer=mixer,
> nbands = -30,
> spinpol = False,
> usesymm = False)
> poissonsolver = PoissonSolver()
> correction = DipoleCorrection(poissonsolver, 2) # 2 == z-axis
> calc = GPAW(poissonsolver=correction)
> calc.attach(calc.write,1,gpwdat)
> slab.set_calculator(calc)
>
> I have attached also a part of the output file and the corresponding 
> structure.
> I haven't tried yet to run first in the LCAO mode and than to continue 
> this way.
>
> Thank you
> Isabela Man