[QE-users] Help in spin polarized calculation for surface dangling bonds

[Giovanni Cantele]

Dear Lorenzo,

the variable starting_magnetization is usually used to drive the system
out of the non magnetic solution, in that starting_magnetization(i) = 0 for
all atomic species
should always bring to a spin unpolarized system. The starting value in
some cases is not so important
(different values will produce the same magnetic ground state), but as far
as I remember it could be
in some (not so frequent) cases where different magnetic energy minima
exist.

For the other questions:
- no special attention paid to the pseudopotential choice, if you mean to
choose a pseudopotential "specific"
for a spin-polarized calculation
- I would not use the input_DFT variable unless you need it for specific
purposes (e.g. non local functionals, like vdw-DF).

Ciao,
Giovanni

-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at spin.cnr.it <giovanni.cantele at spin.cnr.it>
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: https://sites.google.com/view/giovanni-cantele/home


Il giorno sab 19 apr 2025 alle ore 16:37 Lorenzo Sponza <
lorenzo.sponza at onera.fr> ha scritto:

> Dear Quantum ESPRESSO users and developpers,
>
> I need some help to set up a calculation of a Si(111) 1x1 surface. This
> surface is characterized by dangling bonds that spoil the electronic
> states around Fermi. In literature, two approaches are usually adopted.
> One consists in saturating the surface with H atoms, the other consists
> in performing a spin polarized calculation.
> I want to give both methods a try, but I stuck when it comes to set up
> the spin polarized input file. I set nspin=2, but I'm perplexed about
> the value to give to starting_magnetization since I have only Si atoms
> here, and in this specific case it is not clear to me how this variable
> is interpreted and used by the code.
> Finally, is there any attention to be paid in choosing the
> pseudopotential or in specifying the input_DFT variable? I've used PBE
> scalar relativistic PAW pseudos so far.
>
> Many thanks for your help.
>
> --
> Dr. Lorenzo Sponza
>
> Chargé de Recherche au CNRS
> Université Paris-Saclay, ONERA, CNRS Laboratoire d'étude des
> microstructures (LEM)
> 29 Avenue de la division Leclerc, 92322 Châtillon
> Tel: +33146734464
>
> ETSF Research Team Leader
> European Theoretical Spectroscopy Facility
> 17 Sart-Tilman B-4000 Liège, Belgium
>
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