I want to calculate Structural, electronic, and "magnetic" properties of CoZrIrSi quaternary Heusler alloy with First-principles study by VASP Package. my INCAR files for each step of calculations such as RELAX, SCF, DOS, BAND to get proper results.?
- Minimal INCAR for optimizations and SCF:
ICHARG = 2
ISMEAR = 2 ! if this didn't work use ISEMAR=0 with a proper ISIGMA
IBRION = 2
NSW = 100
EDIFF = 1E-5 ! change as appropriate
EDIFFG = -5E-3 ! Change as appropriate
ISPIN = 2
ENCUT = 400 ! change as appropriate
LORBIT = 11
LMAXMIX=6
LREAL = Auto ! use this if your system is large
!----------- possible magnetic configurations; choose one and change as appropriate
MAGMOM = 5 0 ! Assuming a collinear FM setting with the first ion being magnetic
MAGMOM = 5 -5 ! Assuming an AFM setting
MAGMOM = 5 5 0 0 0 0 ! Assuming a non-collinear setting with the first ion being magnetic along [110] direction
!--------Uncomment the following lines if you want to include spin-orbit coupling
#LSORBIT = .TRUE.
#SAXIS = 0 0 1
#GGA_COMPAT=.FALSE.
- For band band structure use ICHARG=11 and a proper KPOINTS file
- For DOS use ICHARG=11 and ISMEAR=-5 using either the same SCF k-mesh or a new one with a denser k-mesh.
Thanks, Dr. Mohammad Saeed Bahramy
in this INCAR, no need for MAGMOM?
Sure, you can add MAGMOM, too (though it's not usually necessary for ferromagnetic systems unless you want to apply a non-collinear setting. For antiferromagnets, on the other hand, it must be given). Also, mind that this INCAR is for a non-relativistic calculation. In case you want to include spin-orbit coupling, you need to add LSORBIT=.TRUE., as well. I edited my previous comment to include these additional options.
Thank you, Dr. Mohammad Saeed Bahramy .for your complete guidance answer.
it is now a question for me why use 5 for MAGMOM? why not 4? how I can optimize MAGMOM?
Of course, you can change that value but it's usually better to choose relatively large magnetic moments for MAGMOM. It can enforce the desired spin configuration throughout the calculation.
Mohammad Ebdali
You may also want to set RWIGS in the INCAR file, so that the OUTCAR file comes to include the charges and magnetic moments on the individual atoms (insides spheres with the set radius RWIGS, centered around the atom nuclei). That allows you to inspect what the moments on each atom converged to, which may be different that what you set in the MAGMOM line in the INCAR file.
In older versions of VASP, RWIGS only worked if NPAR was set to 1, I don't know if that is still required in the latest version.
To obtain some properties (charge, magnetic moment, pDOS, etc) of an 'atom' in a crystal, it is necessary to define the size (radius) of the atom. One way is mentioned by Mohammad, using RWIGS (Radius of Wigner-Seitz) which allows you to have some freedom to define the atom. Another way is using the default values by add 'LORBIT=10' in INCAR. This will also work.
Peter Klaver and Changming Fang thank you for your good answers. I understand from your mentioned that if I use RWIGS then the results are better and I can use them in the next steps?
Dear Mohammad,
Indeed use RWIGS may be better if you chose the R values in a more reasonable way. The default values when use 'LORBIT=10' or so come from the physicists' understanding of the size of an 'atom' in a solid or a molecule.
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