projection on atomic base

[marco_infantino]

Hello,
I would like to know with which function or method is the magnetization printed for each tom and for each orbital, since we are just working with plane waves period code. What is it done in the output ? Just the mulliken analysis or something else ?
I would have a slightly similar question for the projected density of states. Whith which function is it done ? How is possible to project per each atom and orbital ?
Thanks you in advance,
if there are paper in which those procedure are explained, suggestions regarding them will be very happily accepted.
Best,
Marco

[marie-therese.huebsch]

Hi Marco,

Great question. This is often not reflected deeply. VASP is not a plane-wave code but employs the PAW formalism. If you use LORBIT>=10 the on-site magnetic moments are computed by projecting onto the PAW spheres.

In this context, I can recommend reading

• G. Kresse, and D. Joubert, Phys. Rev. B 59, 1758 (1999).

• D. Hobbs, G. Kresse, and J. Hafner, Phys. Rev. B. 62 (2000).

• M. Schüler, O.E. Peil, G.J. Kraberger, R. Pordzik, M. Marsman, G. Kresse, T.O. Wehling, and M. Aichhorn, J. Phys.: Condens. Matter 30, 475901 (2018).

Please let me know if this answers your question!

Ps: Here is how I would write it:

[marco_infantino]

Thank you Marie-Therese for your precise answer.
I would like to ask you if the projection method used for the projected density of state is also that one you indicated with your answer.
I have seen that some of the indicated paper and not too old, therefore I assume that there are no textbook that treat those kind of solid state topics in very details.
Thanks and best,
Marco

[marie-therese.huebsch]

Hi Marco,

glad I could help. Yes, the expression for the partial DOS is the same. That's also an interesting point, since that means it may not add up to the total (unprojected) DOS.

The method to look at the orbital character is probably as old as the PAW method so it could be discussed somewhere in a textbook. It should be seen as a good estimate (that is usually what is reported in ab-initio studies of some material) rather than the golden standard (that would be Bader analysis or wannierization; though they have their own issues). I will make a note to cover it more deeply in future lectures. If you find a textbook that covers it, could you please post it here?

The most recent paper is discussing a technical detail about the phase factor of the wavefunction but maybe the references within are a good overview.