You need two define two different (but equal) atomic species if you expect some antiferromagnetic ordering (thus starting from opposite starting_magnetization on the two).
Usually, if you seek a magnetic solution, you can just set starting_magnetization to 0.5 or 0.7 and the self consistent charge density automatically will produce a solution in which the spin density will be localized only on the atoms carrying a magnetic moment. So, while you need to distinguish between atoms with opposite magnetizations, you shouldn't need, usually, to distinguish between atoms with no net magnetization and atoms with net magnetization. I would, at a first glance, try sto set starting_magnetization = 0.7 on all Si atoms and see what happens. 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: [email protected] <[email protected]> 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 19:46 Lorenzo Sponza < [email protected]> ha scritto: > Thanks Giovanni for your quick answer. > > Still, it's not clear to me how to set the starting magnetization. > Putting just starting_magnetization=X will be useless because this will > set a starting magnetization in all Si atoms, that will break no > symmetry. > On the other hand, if I understood well I can define two atomic species, > say Si1 and Si2, and define the starting magnetization for only one of > the two. I think that this is the thing I should do, but I can not > figure out which atoms should belong to one group or the other and > wheather I need more than two groups for this specific problem. > I was hoping to get help from someone who had already done similar > simulations. > Cheers > > Le 2025-04-19 17:25, Giovanni Cantele a écrit : > > 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: [email protected] > > 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 > > <[email protected]> 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 > >> > > > _______________________________________________________________________________ > >> The Quantum ESPRESSO Foundation stands in solidarity with all > >> civilians worldwide who are victims of terrorism, military > >> aggression, and indiscriminate warfare. > >> > > > -------------------------------------------------------------------------------- > >> Quantum ESPRESSO is supported by MaX (www.max-centre.eu [1]) > >> users mailing list [email protected] > >> https://lists.quantum-espresso.org/mailman/listinfo/users > > > > > > Links: > > ------ > > [1] http://www.max-centre.eu > > > _______________________________________________________________________________ > > The Quantum ESPRESSO Foundation stands in solidarity with all > > civilians worldwide who are victims of terrorism, military aggression, > > and indiscriminate warfare. > > > -------------------------------------------------------------------------------- > > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > > users mailing list [email protected] > > https://lists.quantum-espresso.org/mailman/listinfo/users > > -- > 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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