[Wien] Spin-polarized DOS for dopants in non-magnetic materials

[Marcelo Barbosa]

Dear all,

I’m calculating the DOS for dopants in semiconductors to get the corresponding impurity bands.
I’m dealing with non-magnetic materials and non-magnetic dopants, so I would assume that no spin-polarization was needed.
However, in some cases when substituting an atom for a dopant with different valence number, the DOS reveals an impurity band with different contributions from spin-up and spin-down due to the extra/missing electron. Also, the energy difference from the valence band maximum to the impurity band changes from a non spin-polarized calculation to a spin-polarized calculation.
My question then is: should I consider the spin-polarized results every time the spin-up and spin-down contributions are different? Or is there any good argument to choose the non spin-polarized calculation instead?

Regarding the impurity bands themselves, in the case of partially filled impurity bands, what is the correct energy value to report regarding the impurity band: the difference from the valence band maximum to the beginning of the entire impurity band or the difference from the valence band maximum to the minimum energy level of the unfilled region of the impurity band? 

Thank you for your help.

Best regards,
Marcelo