[QE-users] SCF calculation with SOC fails to converge

[Giovanni Cantele]

Hi,
after checking your output, it seems that at the point where your run
stopped there is no clear indication of a specific error.
This is indeed a difficult case. SOC calculations often require more effort
to converge. (try: grep estimated soc.out, the error is decreasing).

I would first try increasing electrons_maxstep to 200. With some luck, the
run might converge within the next 30–40 steps. If it still fails to
converge, please let me know.

Before restarting the calculation, I would also suggest the following
changes to the input:

* as noted in soc.out, your pseudopotentials are norm-conserving, so you
should use the default
ecutrho = 4 * ecutwfc = 280 Ry.
Using 400 Ry only makes the run heavier without improving accuracy.

* I would avoid specifying nbnd in an SCF run. With occupations='smearing',
pw.x already increases the number of occupied bands by ~20%.
In your case, you have 88 electrons, which (with SOC included) corresponds
to 88 occupied bands. Setting nbnd = 160, which is nearly double, again
makes the calculation unnecessarily heavier without any benefit.

Giovanni

-- 

Prof. Giovanni Cantele
Dipartimento di Fisica "Ettore Pancini"
Universita' degli Studi di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at unina.it
Phone: +39 081 676910

Web page: https://sites.google.com/view/giovanni-cantele/home


Il giorno mer 3 dic 2025 alle ore 12:53 Wang, Aolei via users <
users at lists.quantum-espresso.org> ha scritto:

> Dear all, I am currently performing an SCF calculation with SOC for a 2D In
> ₂Se₃ system, but I am encountering convergence issues. First, I
> successfully performed a non-SOC SCF calculation that converged properly.
> Then, for the SOC calculation, I used startingpot='file' to read the charge
> density from the previous calculation. However, the SOC SCF fails to
> converge.
>
> Here are some details about my setup: QE version: 7.5; The system is
> metallic, so I used smearing='mv' with degauss=0.02; Due to the dipole
> moment in the system, I included the relevant electric field parameters;
> Pseudopotentials: ONCV fully-relativistic version.
>
> Could you please help me identify what might be causing this convergence
> issue? Any suggestions would be greatly appreciated.
>
> Below is the input file for the SOC run:
>
> &CONTROL
>
> calculation = 'scf'
>
> prefix = 'in2se3'
>
> restart_mode = 'from_scratch'
>
> outdir = './soc'
>
> pseudo_dir = './pseudo'
>
> verbosity = 'high'
>
> etot_conv_thr = 1e-7
>
> forc_conv_thr = 1e-4
>
> tefield = .true.
>
> dipfield = .true.
>
> /
>
> &SYSTEM
>
> ibrav = 0
>
> nat = 10
>
> ntyp = 2
>
> nbnd = 160
>
> ecutwfc = 70
>
> ecutrho = 400
>
> occupations = 'smearing'
>
> smearing = 'mv'
>
> degauss = 0.02
>
> noncolin = .true.
>
> lspinorb = .true.
>
> vdw_corr = 'dft-d3'
>
> edir = 3
>
> emaxpos = 0.95
>
> eopreg = 0.05
>
> eamp = 0.0
>
> /
>
> &ELECTRONS
>
> electron_maxstep = 100
>
> conv_thr = 1e-5
>
> diagonalization = 'david'
>
> mixing_mode = 'local-TF'
>
> mixing_beta = 0.1
>
> mixing_ndim = 12
>
> startingpot = 'file'
>
> startingwfc = 'atomic+random'
>
> /
>
> ATOMIC_SPECIES
>
> In 114.818   In_PBE_FR.SG15v1.2.UPF
>
> Se 78.971    Se_PBE_FR.SG15v1.2.UPF
>
> K_POINTS { automatic }
>
>    12   12   1   0.000000   0.000000   0.000000
>
> CELL_PARAMETERS (angstrom)
>
>     4.085499    0.0000000000    0.0000000000
>
>     2.0427495    3.5381459211359205    0.0000000000
>
>     0.0000000000    0.0000000000   40.0000000000
>
> ATOMIC_POSITIONS (crystal)
>
> In               0.3333263268        0.3333296582        0.3219938051
>
> In               0.6666658723        0.6666698966        0.4272754855
>
> In               0.3333356888        0.3333320384        0.5674363654
>
> In               0.0000045743        0.0000004570        0.6728520187
>
> Se              -0.0000069198       -0.0000034614        0.2909006171
>
> Se               0.3333302669        0.3333357327        0.3854509284
>
> Se              -0.0000006411        0.0000028903        0.4604813408
>
> Se               0.6666690540        0.6666654851        0.5365419061
>
> Se               0.3333380834        0.3333335986        0.6309004416
>
> Se               0.6666710277        0.6666670377        0.7061670915
>
> Thank you in advance for your time and assistance.
>
>
>
> Best regards,
>
> Aolei Wang
>
> Research Scholar
>
> Department of Physics & Astronomy
>
> California State University, Northridge
>
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