[QE-users] convergence issue in DFT_U+V calculation
Matteo Cococcioni
matteo.cococcioni at unipv.it
Wed Dec 1 12:24:03 CET 2021
Dear Bhamu,
you better use two different kinds for the Fe in octahedral sites: one for
2+ the other for 3+. they are likely to have different U's as well.
Matteo
Il giorno mer 1 dic 2021 alle ore 11:34 Dr. K. C. Bhamu <kcbhamu85 at gmail.com>
ha scritto:
> Dear Dr. Matteo,
>
> Thank you very much for the quick response.
>
> Yes, I am doing vc-relax in between each step. Doing vc-relax without
> adopting geometry information from the previous run. I am only supplying
> the HP file containing U+V obtained from the previous run for the vc-relax
> for the next step.
>
> Fe1 (octahedral coordination) atom has a mixed charge state (Fe3+ and
> Fe2+).
> The magnetic moment of Fe1( Fe3+) cancels out with Fe2 (tetrahedral
> coordination; all Fe3+) and the resultant magnetic moment comes from Fe1
> (2+) atoms.
> According to Ref. [1]
> <https://www.sciencedirect.com/science/article/abs/pii/S0039602812000544>,
> I set all Fe1 as up and all Fe2 as down spins.
>
> Do you think my input still has some issues?
>
> -------------------
> I am providing some additional information here.
>
> Additional information:
>
> Ref. [1]
> <https://www.sciencedirect.com/science/article/abs/pii/S0039602812000544>
> Just below Fig. 3 it is mentioned that "For Fe3O4 having ferrimagnetic
> property, the spin of the octahedral and tetrahedral Fe was set as up and
> down, respectively."
>
>
> Relevant para from Ref. [2]
> <https://link.springer.com/article/10.1134%2FS1027451010030079> is as
> below:
> Fe2+ cations in the face-centered cubic lattice formed by oxygen anions
> occupy octahedral sites, while Fe3+ cations are distributed between
> octahedral and tetrahedral sites. The trivalent Fe3+ ion is in the state
> with a spin S = 5/2 and zero orbital moments. The bivalent Fe2+ ion has a
> spin of 2, and its contribution comes to ~4μB unless one considers a
> certain possible contribution from the orbital moment [2]. The measured
> value of the magnetic moment for magnetite is 4.1μB. The magnetic moments
> of Fe3+ ions are antiparallel to each other, and the observed moment is
> determined by Fe2+ ions only (Fig. 1).
>
>
> Thanks and regards
> Bhamu
>
>
>
> On Wed, Dec 1, 2021 at 2:17 PM Matteo Cococcioni <
> matteo.cococcioni at unipv.it> wrote:
>
>> the fourth iteration does not look too good to me as the U for Fe2 is
>> suddenly going from 4.31 to 0.7.
>> Fe3O4 is a difficult system of its own. are you sure that all the Fe1 are
>> of the same kind (3+)? The system is for sure
>> a mixed valence one but I don't remember how this matches its magnetic
>> structure. Are you relaxing the structure in between?
>> Maybe because of the structure changes hp is not recognizing the
>> neighbors it had before for each Fe.
>>
>> Regards,
>>
>> Matteo
>>
>> Il giorno mer 1 dic 2021 alle ore 06:07 Dr. K. C. Bhamu <
>> kcbhamu85 at gmail.com> ha scritto:
>>
>>> Dear Iurii,
>>> This is from the calculation without nbnd in QE input file (QE input and
>>> HP input are supplied at the end of this email).
>>> I am trying to get a converged value of U+V. Up to four steps, all the
>>> calculations seem to be fine (other than the converged value of U+V). But
>>> in the 5th step, I see that my calculations are not converging.
>>>
>>> I am getting this message:
>>> atom # 5 q point # 3 iter # 180
>>> chi: 1 -83.8242814567 residue: 103.6191835332
>>> chi: 2 -83.8242814548 residue: 103.6191835384
>>> chi: 3 ************** residue: 381.0626501229
>>> chi: 4 ************** residue: 326.7198566114
>>> chi: 5 317.5473216386 residue: 329.6382092529
>>> chi: 6 ************** residue: 580.5784405595
>>> chi: 7 9.0496504843 residue: 1.9763844786
>>> chi: 8 -6.2884312048 residue: 21.8495062869
>>> chi: 9 9.0496505082 residue: 1.9763845088
>>> chi: 10 -6.2884312084 residue: 21.8495062832
>>> chi: 11 10.2338160751 residue: 7.3557134894
>>> chi: 12 -5.1687829951 residue: 22.9825921172
>>> chi: 13 6.7503553298 residue: 7.1360232476
>>> chi: 14 -3.9982889995 residue: 27.0388948104
>>> Average number of iter. to solve lin. system: 23.6
>>> Total CPU time : 63284.6 s
>>> ###################
>>> atom # 5 q point # 3 iter # 274
>>> chi: 1 ************** residue: **************
>>> chi: 2 ************** residue: **************
>>> chi: 3 ************** residue: **************
>>> chi: 4 ************** residue: **************
>>> chi: 5 ************** residue: **************
>>> chi: 6 ************** residue: **************
>>> chi: 7 ************** residue: 78.8265104616
>>> chi: 8 190.5140692168 residue: **************
>>> chi: 9 ************** residue: 78.8264974402
>>> chi: 10 190.5140679621 residue: **************
>>> chi: 11 ************** residue: **************
>>> chi: 12 544.1915326984 residue: **************
>>> chi: 13 ************** residue: **************
>>> chi: 14 ************** residue: **************
>>>
>>> U+V value from four completed calculations is given below:
>>>
>>>
>>> site n. type label spin new_type new_label Hubbard U (eV)
>>> 1 1 Fe1 1 1 Fe1 5.1791
>>> 5 2 Fe2 -1 2 Fe2 5.0962
>>> 7 3 O 0 3 O 7.1203
>>>
>>> site n. type label spin new_type new_label Hubbard U (eV)
>>> 1 1 Fe1 1 1 Fe1 5.6013
>>> 5 2 Fe2 -1 2 Fe2 4.3164
>>> 7 3 O 0 3 O 7.5401
>>>
>>> site n. type label spin new_type new_label Hubbard U (eV)
>>> 1 1 Fe1 1 1 Fe1 5.6013
>>> 5 2 Fe2 -1 2 Fe2 4.3164
>>> 7 3 O 0 3 O 7.5401
>>>
>>> site n. type label spin new_type new_label Hubbard U (eV)
>>> 1 1 Fe1 1 1 Fe1 4.4843
>>> 5 2 Fe2 -1 2 Fe2 0.7259
>>> 7 3 O 0 3 O 7.3480
>>>
>>>
>>> I do not think changing "conv_thr_chi" will help here as the number is
>>> still oscillating in integer values.
>>>
>>> What suggestions do you have for this situation?
>>>
>>>
>>> HP input file:
>>>
>>> &inputhp
>>> prefix = 'pwscf',
>>> niter_max=300
>>> outdir = './temp/',
>>> nq1 = 2, nq2 = 2, nq3 = 2,
>>> conv_thr_chi = 1.0d-5,
>>> find_atpert = 1
>>> docc_thr=1.d-3
>>> !disable_type_analysis=.true.,
>>> /
>>>
>>> QE input file:
>>> &CONTROL
>>> calculation = 'vc-relax'
>>> restart_mode='from_scratch',
>>> etot_conv_thr = 1.4000000000d-04
>>> forc_conv_thr = 1.0000000000d-04
>>> outdir = './temp/'
>>> prefix = 'pwscf'
>>> pseudo_dir = '~/PPs/jana_2/'
>>> tprnfor = .true.
>>> tstress = .true.
>>> verbosity = 'high'
>>> /
>>> &SYSTEM
>>> degauss = 0.022
>>> ecutrho = 320
>>> ecutwfc = 40
>>> occupations = 'smearing' , smearing = 'mp'
>>> ibrav = 0
>>> nat = 14
>>> nosym = .false.
>>> ntyp = 3
>>> nspin=2
>>> starting_magnetization(1) = 0.8
>>> starting_magnetization(2) = -0.8
>>> starting_magnetization(3) = 0.0
>>>
>>> lda_plus_u = .true.,
>>> lda_plus_u_kind = 2,
>>> U_projection_type = 'ortho-atomic',
>>> !Hubbard_V(1,1,1) = 1.d-8
>>> !Hubbard_V(5,5,1) = 1.d-8
>>> !Hubbard_V(7,7,1) = 1.d-8
>>> Hubbard_parameters = 'file'
>>>
>>>
>>> /
>>> &ELECTRONS
>>> conv_thr = 1.0000000000d-06
>>> electron_maxstep = 400
>>> mixing_beta = 1.5000000000d-01
>>> /
>>> &IONS
>>> ion_dynamics = 'bfgs'
>>> /
>>> &CELL
>>> /
>>>
>>> ATOMIC_SPECIES
>>> Fe1 55.845 Fe.pbe-nd-rrkjus.UPF
>>> Fe2 55.845 Fe.pbe-nd-rrkjus.UPF
>>> O 15.9994 O.pbe-rrkjus.UPF
>>> ATOMIC_POSITIONS (crystal)
>>> Fe1 0.0000000000 -0.0000000000 -0.0000000000
>>> Fe1 0.5000000000 0.0000000000 0.0000000000
>>> Fe1 0.9999999892 0.5000000216 -0.0000000000
>>> Fe1 0.9999999965 0.9999999956 0.5000000115
>>> Fe2 0.3749993721 0.3749993349 0.3750019210
>>> Fe2 0.6250006225 0.6250006532 0.6249981020
>>> O 0.2454868415 0.2454868399 0.2454949640
>>> O 0.7545131845 0.7545131098 0.7545050345
>>> O 0.7635313546 0.2454868399 0.2454949640
>>> O 0.2364686713 0.7545131098 0.7545050345
>>> O 0.2454868307 0.7635313746 0.2454949640
>>> O 0.7545132523 0.2364686217 0.7545050345
>>> O 0.2454908593 0.2454908222 0.7635274591
>>> O 0.7545090629 0.7545091741 0.2364725394
>>>
>>> CELL_PARAMETERS (angstrom)
>>> 5.944682649 0.000000000 0.000000000
>>> 2.972341325 5.148246192 0.000000000
>>> 2.972341325 1.716082064 4.853885701
>>>
>>> K_POINTS automatic
>>> 7 7 7 0 0 0
>>>
>>>
>>> Regards
>>> Bhamu
>>>
>>> _______________________________________________
>>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
>>> users mailing list users at lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>
>>
>>
>> --
>> Matteo Cococcioni
>> Department of Physics
>> University of Pavia
>> Via Bassi 6, I-27100 Pavia, Italy
>> tel +39-0382-987485
>> e-mail matteo.cococcioni at unipv.it <lucio.andreani at unipv.it>
>> _______________________________________________
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
>
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
--
Matteo Cococcioni
Department of Physics
University of Pavia
Via Bassi 6, I-27100 Pavia, Italy
tel +39-0382-987485
e-mail matteo.cococcioni at unipv.it <lucio.andreani at unipv.it>
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