Initial State Setup (Relative spin Selection)

[Om Prakash Upadhyay]

I want to analyze the band structure and DOS of Cu2O nanowire using ATK_DFT with exchange correlation basis set SGGA_RPBE along with Initial state. While passing through initial state I don't understood that how the user spin should be selected?? The question is that in either cases should we have to take the relative spin for all atoms 1 or any other else too??? If then what relative spin should we have to select for Cu & O in Cu2O? Please  kindly give the reply...............
                     waiting for reply...................
                                    Thnks......................

[zh]

Before studying the magnetic properties of Cu2O nanowires, it is better to first check magnetic properties of bulk Cu2O.   I think the bulk Cu2O materials is nonmagnetic.   For nanowire structure,  the surface atoms may have localized states and thus induce local magnetic moments.

[Om Prakash Upadhyay]

As I know Cu2O in bulk is dia-magnetic (-ve susceptibility) (non-magnetic).
While making the analysis of its nanowire for the study of magnetism , Is it possible to take SGGA-RPBE exchange correlation basis set or not??? If the bulk is non magnetic then can't we analyze the magnetic property for its nao-structures?
Please clearify me in detail.
And please suggest me that what method is suitable for the study of Cu2O nanowire to analyze bandstructure, DOS & mullikanpopulation.
                             waiting for expected reply...........................

[Jess Wellendorff]

1) Yes, you can use SGGA-RPBE for spin-polarized calculations for a nanowire as well as for a periodic bulk. If the ground state is indeed magnetic, you will find different spin-up and spin-down electron densities. If it is not magnetic, both spin channels will be equally occupied in the ground state. I suggest using a polarized InitialState (in the Scripter) to make the SCf start out from a polarized electron density. Sometimes this is needed to find the "true" polarized ground state, if one exists.
2) Sounds like you need a fairly simple workflow: Build nanowire --> Setup DFT calculator (with/without spin-polarization) --> Add Bandstructure, DOS, and Mulliken analysis objecets --> Run calculation. You may need a GeometryOptimization step as well, before performing the post-SCF analyses.