[Wien] Clarification on Magnetic Anisotropy Energy calculations

[Marcus Ekholm]

Dear all,

I would like to ask for a clarification on the various strategies to calculate magnetic anisotropy energy (MAE) using the force theorem with DFT+U. We get values for the MAE in the order of 10^-7 eV with Wien2k, while with FLEUR and Quantum Espresso we get 10^-4 eV (for a slab), so somewhere there is an error.

Based on previous posts to the mailing list, we try the following:

***** STRATEGY 1

1. init
2. runsp_lapw -orb -p -ec 0.000001
3. init_so (which will change EMAX and set an appropriate kmesh)

4. set magnetization in case.inso

5. x lapwso -up -p -orb
6. x lapw2 -up -so -p and x lapw2 -dn -so -p
7. Add the two :SUM values in case.scf2up/dn

Repeat #4-#7 to get energy differences


***** STRATEGY 2

1. init
2. init_so, but set case.inso to skip SO for all atoms.
3. runsp_lapw -orb -p -ec 0.000001 -so

4. set magnetization in case.inso

5. x lapw1 -up -c and x lapw1 -dn -c
6. x lapwso -up -p -orb
7. x lapw2 -up -so -p and x lapw2 -dn -so -p
8. Add the two :SUM values in case.scf2up/dn

Change magnetization direction in case.inso and repeat #6-#8.

***

Do these strategies make sense?

Best regards


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