Scf does not converge when using DFT+U

[Chengqian-Zhang]

Describe the bug

In Pb9Cu(PO4)6O system, scf converges when not using DFT+U but scf does not converges when using DFT+U(d orbital of Cu). I have tried different settings including
1.hubbard_u=2.0 4.0 6.0
2.mixing_beta=0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.05 0.01 0.001 0.0001
3.smearing_sigma=0.03 0.02 0.0146
but all attempts do not converge

Expected behavior

Scf can converge when using DFT+U

To Reproduce

All input and output files:
PbCuPO.zip

Environment

Image: registry.dp.tech/dptech/abacus:3.2.3
Platform: Bohrium

Additional Context

No response

[wenfei-li]

#2639 similar problem

[wenfei-li]

This might require the implementation of new mixing algorithms, which is only possible after the refactoring of LCAO code. So this issue will be marked later.

[WHUweiqingzhou]

@Chengqian-Zhang,

After test by using latest ABACUS after PR #3226, the calculations are still hard to converge with U.
According to the mixing roadmap Issue #3138, this issue calls for the mixing of Hamiltonian/Density Matrix.

[dyzheng]

Please pay attention to #3588 , the new DFT+U method would improve the convergence of SCF calculation.

[dyzheng]

You can try the latest version v3.6.0 , this case can converge.