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why I obtain a magnetic results when I include the SOC?

Posted: Sun Sep 15, 2024 9:21 am
by Kun Tao

Hi, everyone,

Now, I am trying to built a two dimensional materials with including the SOC calculation, but I got a magnetic results. However, when I performed a spin polarized calculation, I found that the material is non-magnetic. Any suggestions will be appreciated!

With regards,
Kun Tao


Re: why I obtain a magnetic results when I include the SOC?

Posted: Wed Sep 18, 2024 7:13 am
by marie-therese.huebsch

Whether the ground state is magnetic depends on the Hamiltonian. Additionally many XC functionals tend towards symmetry-broken solutions (i.e. magnetic solutions). See for instance the basic tutorial about an isolated oxygen atom.

If you want to impose a nonmagnetic solution, you could probably use symmetry to symmetrize it away, which is like a constraint on the solution. This is then not the true ground state whithin the approximation, but the ground state within the constraint.

It may as well be that the spin-polarized system converged to a metastable nonmagnetic solution (local minimum). You can try to do the spin-polarized calculation with intial magnetic moments (MAGMOM) set to 1.3 x the on-site magnetization (LORBIT=11) that you find in the ncl-SOC calculation. Then compare the total energy of the spin-polarized calculations. Is the nonmagnmetic solution really the ground state?

Best regards,
Marie-Therese