Extracting Orbital Contributions to Magnetic Moments in 2H-FeCl2 Monolayer using VASP

[farah_shahzadi]

Hello VASP Community,

I am currently working on a 2H-FeCl2 monolayer and would like to understand the orbital contributions to the magnetic moment from my VASP calculations. Specifically, I need to know how to identify the orbitals (e.g., eg and t2g) that contribute to the magnetic moment.

Could someone guide me on the following:

How can I determine which orbitals are contributing to the magnetic moment in my system?
How do I extract and analyze the density of states (DOS) for specific orbitals like eg and t2g from the VASP output files?

Any detailed steps, example scripts, or references to relevant sections in the VASP documentation would be highly appreciated.

Thank you for your assistance!
Farah Shehzadi

[manuel_engel1]

Hello Farah,

Thanks for reaching out. Have you had a look at the LORBIT tag? It allows to "decompose the KS orbitals into local quantum numbers (lm) and obtain local properties, e.g., the on-site charge density or on-site magnetic moments due to the spin degrees of freedom". The decomposition also works for the DOS and is written to the DOSCAR file. The exact format of these data is specified on the corresponding wiki pages that I have linked to.

Is this what you are looking for? If not, feel free to reach out again.

[farah_shahzadi]

Thank you for our response but i want to determine the individual contributions of the d orbitals (dxy, dyz​, dzx​, dx2−y2​, dz2​) to the total magnetic moment?

[manuel_engel1]

Setting LORBIT generates the PROCAR file that should contain the information you seek. Note that the individual contributions do not necessarily add up to one. In order to achieve normalization to one purely in VASP without the help of any external tools, you can set LORBIT<10 and carefully tune the RWIGS parameter. More information is given on the VASP wiki. However:

Please keep in mind that results are qualitative i.e. there is no unambiguous way to determine the location of an electron (and hence the local magnetic moments). With the current implementation, it is for instance hardly possible to determine charge transfer. What can be derived from the partial DOS is the typical character of a peak in a DOS. Quantitative results can be obtained only by careful comparison with a reference system (e.g. bulk versus surface).