symmetry has a strong effect on the band structure of magnetic systems

[liusss324]

Details

Dear developers,

I have found that symmetry has a strong effect on the band structure of magnetic systems. I tested several symmetry settings.

1. With symmetry 1 in both SCF and NSCF, the obtained band structure is incorrect: a splitting appears between K and K′.

2. With symmetry 0 (or -1) in both SCF and NSCF, the obtained band structure is correct, as shown below.

3. With symmetry -1 in SCF and symmetry 1 in NSCF, the obtained band structure is the same as in case 2. This suggests that using symmetry 1 may produce an incorrect charge density in magnetic systems.

However, if symmetry 0 or -1 is used during structure optimization, the structure relaxes to C1. For example, in a trigonal system, a will no longer equal b. If symmetry 1 is used to optimize the structure, the incorrect charge density may not yield the correct structure.

So, how should we handle magnetic systems?

Have you read FAQ on the online manual http://abacus.deepmodeling.com/en/latest/community/faq.html

• Yes, I have read the FAQ part on online manual.

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[mohanchen]

Thanks for the report! Could you upload your files for us to test? @liusss324