I want to calculate the magnetic anisotropy energy of the CrI$_3$ monolayer which has 8 atoms per unit cell. I have understood from VASPWIKI that there are two steps:

  1. A standard SCF collinear calculation is used to generate the WAVECAR and CHGCAR files.

  2. A non-collinear calculation by adding these tags: LSORBIT = .TRUE. ,ICHARG = 11, LMAXMIX = 4 and SAXIS.

I also understand that step 2 must be run three times with: SAXIS=0 0 1, SAXIS=0 1 0 and SAXIS=1 0 0. But I didn't understand how to set the MAGMOM tag in the second step. Knowing that in the first step I specified MAGMOM = 2*5.0 6*0.6 because I have 8 atoms (two are magnetic and six are non-magnetic).

Could you please help me in choosing the right setting of the MAGMOM tag?


1 Answer 1


You don't need to set the MAGMOM tag in the second step.

This is because the charge density (including the spin density which is the charge difference between spin-up and spin-down) is read in from CHGCAR and kept constant throughout the calculation due to ICHARG = 11.

  • $\begingroup$ Thank you for your answer, and I am sorry for my late response. $\endgroup$
    – Chi Kou
    Apr 5, 2022 at 6:27
  • $\begingroup$ One more question plz: Can I use the HSE06 method to calculate MAE? $\endgroup$
    – Chi Kou
    Apr 5, 2022 at 6:28
  • $\begingroup$ @ChiKou Yeah, I think you can :) $\endgroup$ Apr 6, 2022 at 13:40
  • $\begingroup$ if I want to calculate the difference between z-axis and xy plane, am I right if I set SAXIS = 0 0 1 for z-axis and SAXIS = 1 1 0 for xy plane? $\endgroup$
    – Chi Kou
    Apr 7, 2022 at 10:27
  • $\begingroup$ Yep, looks good to me. $\endgroup$ Apr 7, 2022 at 17:32

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