Want some help in accelerating the SCF convergence in Fe-bearing systems using DFT+U.

[Weizhang88]

Details

I am using Abacus (3.7.4) to perform DFT labeling work with dpgen for an Fe-bearing mineral using DFT+U. However, the system is challenging to converge, with approximately 36-56% of tasks failing in some dpgen iterations. I would appreciate suggestions to accelerate the SCF convergence and any insights on whether the magnetism of Fe in my calculations is accurate.

scf_Fe.zip

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

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

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[kirk0830]

smearing_sigma can be set as 0.015 Ry at most commonly, and you may consider the u_ramping method if you are sure without dft+u the scf can converge: https://abacus.deepmodeling.com/en/latest/advanced/input_files/input-main.html#uramping

[QuantumMisaka]

@Weizhang88 By tackle with systems contain Fe, you can set smearing method to mp and smearing sigma to 0.01.

The u_ramping method may help, but for dft-label task, is a fixed U value more physical ?

[Weizhang88]

@Weizhang88 By tackle with systems contain Fe, you can set smearing method to mp and smearing sigma to 0.01.

The u_ramping method may help, but for dft-label task, is a fixed U value more physical ?

Many thanks to @kirk0830 and @QuantumMisaka. The changes to the smearing method and smearing sigma significantly improved SCF convergence. However, the effect of u_ramping is not very noticeable and requires more SCF iterations. Given that my dpgen iterations cover a wide range of temperatures and pressures, the values of U may change. Could I use the yukawa_potential to estimate the values of U instead of a fixed U value?

[dyzheng]

@Weizhang88 Hello, yukawa_potential feature can be used to estimate U values, it is not recommanded for DPGEN data generation because the U values should not change for one DP model.