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

Iurii TIMROV iurii.timrov at epfl.ch
Wed Dec 1 10:58:40 CET 2021


Dear Bhamu,


> conv_thr =   1.0000000000d-06


In addition to Matteo's comments I would suggest to converge better the ground state. Indeed, something strange is happening at the 4th iteration - a detailed inspection of the output files is needed, but please check what Matteo wrote.


HTH


Iurii


--
Dr. Iurii TIMROV
Senior Research Scientist
Theory and Simulation of Materials (THEOS)
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334
________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of Matteo Cococcioni <matteo.cococcioni at unipv.it>
Sent: Wednesday, December 1, 2021 9:47:06 AM
To: Quantum ESPRESSO users Forum
Subject: Re: [QE-users] convergence issue in DFT_U+V calculation

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<mailto: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<http://www.max-centre.eu>)
users mailing list users at lists.quantum-espresso.org<mailto: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<mailto:lucio.andreani at unipv.it>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20211201/5f442970/attachment.html>


More information about the users mailing list