[QE-users] dipole correction - "saggy" electrostatic potential?

[Dr. Thomas Brumme]

Dear Chris,

The potential shows the typical quadratic dependence on z since you're  
calculating a charged system - there is a homogeneous background  
charge since the 3D pbc system is assumed to be neutral. This has  
nothing to do with the dipole correction. Depending on what you want  
to do next it might be useful to set the flag assume_isolated='2D'

Regards

Thomas

Zitat von Christoph Wolf <wolf.christoph at qns.science>:

> Dear all,
>
> I am still observing something strange in my slab + dipole correction
> calculation that I do not fully understand.
>
> When using dipfield+tefield (eopreg and emaxpos well within the vacuum
> region) I encounter a "saggy" electrostatic potential (plot_num=11) despite
> the sawtooth efield potential (plot_num=12) looking as usual. Maybe someone
> can give it a look and confirm if this is due to the excess charge in the
> system (this does not happen when running the same system in VASP)?
>
> I attach input and the plot of the potential for 2 and 4 layers of vacuum
> (more vacuum does seem to improve the situation).
>
> Thank you in advance for your time and assistance!
>
> Chris
>
> PS: I am using a QE version with dipole bug fix:
>
>      Program PWSCF v.6.2.2 starts on 25Jun2018 at 10:39:24
>
> --
> Postdoctoral Researcher
> Center for Quantum Nanoscience, Institute for Basic Science
> Ewha Womans University, Seoul, South Korea

--
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig

Tel:  +49 (0)341 97 36456

email: thomas.brumme at uni-leipzig.de