[QE-users] convergence issue in DFT_U+V calculation

Matteo Cococcioni matteo.cococcioni at unipv.it
Wed Dec 1 09:47:06 CET 2021


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
>
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-- 
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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