VASP Forum

I set LHYPERFINE to true, and, to my surprise, I got a huge (~40 T) hyperfine Fermi-contact field despite my material being a semiconductor with a 1 eV gap. I am using tetrahedrons, so no "leaking" due to finite temperature.
I think this is because VASP places the Fermi level exactly at the top of the valence band, so the calculation is picking some spurious electron density from the valence band. A simple solution would be to add another parameter like SHYPERFINE = shift of the Fermi energy to apply before the hyperfine field calculations. Adding SHYPERFINE = 0.5 would likely solve the problem.

Hi,

Can you provide a minimal reproducing example? (check below link for more details)
https://www.vasp.at/wiki/index.php/Mini ... le_example

For an insulating system with fixed occupations, shifting the Fermi level within the gap would not normally be expected to change occupied-state quantities, so it would be useful to verify whether the large contact field originates from the electronic structure itself or from the hyperfine implementation.

Best regards,
Zahed

Thank you. Let me collect more information and get back to you with a clean question.