[QE-users] Query for skip_type and equiv_type for DFT+U+V

Dr. K. C. Bhamu kcbhamu85 at gmail.com
Wed Nov 24 15:31:30 CET 2021


Thanks  Iurii,
I find that "find_atpert" is by default set at 1.
With the setting mention in my previous mail, I got the below error:
 Error in routine hp_find_inequiv_sites (1):
     skip_type must not be setup from the input when find_atpert=1.
For magnetite structure (Fe3O4), Fe has two states: Fe2+ and Fe3+.

 Here is the Tr[ns(na)] and input file
atom    1   Tr[ns(na)]=   6.2349321
atom    1   Mag[ns(na)]=   3.5251042
atom    2   Tr[ns(na)]=   6.2349321
atom    2   Mag[ns(na)]=   3.5251042
atom    3   Tr[ns(na)]=   6.2349321
atom    3   Mag[ns(na)]=   3.5251042
atom    4   Tr[ns(na)]=   6.2348428
atom    4   Mag[ns(na)]=   3.5251547
atom    5   Tr[ns(na)]=   6.1942515
atom    5   Mag[ns(na)]=  -3.5314272
atom    6   Tr[ns(na)]=   6.1942515
atom    6   Mag[ns(na)]=  -3.5314272
atom    7   Tr[ns(na)]=   5.0802986
atom    7   Mag[ns(na)]=   0.0754368
atom    8   Tr[ns(na)]=   5.0802986
atom    8   Mag[ns(na)]=   0.0754368
atom    9   Tr[ns(na)]=   5.0802986
atom    9   Mag[ns(na)]=   0.0754368
atom   10   Tr[ns(na)]=   5.0802986
atom   10   Mag[ns(na)]=   0.0754368
atom   11   Tr[ns(na)]=   5.0802986
atom   11   Mag[ns(na)]=   0.0754368
atom   12   Tr[ns(na)]=   5.0802986
atom   12   Mag[ns(na)]=   0.0754368
atom   13   Tr[ns(na)]=   5.0802792
atom   13   Mag[ns(na)]=   0.0754401
atom   14   Tr[ns(na)]=   5.0802792
atom   14   Mag[ns(na)]=   0.0754401

Input file:

&CONTROL
  calculation = 'vc-relax'
  restart_mode='from_scratch',
  etot_conv_thr =   0.0001
  forc_conv_thr =   0.001
  outdir = './temp/'
  prefix = 'pwscf'
  pseudo_dir = '~/PP/'
  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



>
> > As all Fe will have the same Hubbard parameter (as reported in the
> literature for the same system)...
>
>
> In the literature people often use empirical U, so that's why they use a
> single value of U for all Fe atoms. With the HP code you can do things
> better, i.e. to find out if there are non-equivalent Fe atoms that require
> their own first-principles U.
>
>
> HTH
>
>
> Iurii
>
>
> P.S.: "Dr." is used with the last name not with the first name, so in my
> case this will be "Dear Dr. Timrov". But if you want to address me using my
> first name then just write "Dear Iurii". Sorry, I don't want to bother
> you with this, but just to makes things clear 😊
>
>
> --
> 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 Dr.
> K. C. Bhamu <kcbhamu85 at gmail.com>
> *Sent:* Wednesday, November 24, 2021 1:00:13 PM
> *To:* Quantum Espresso users Forum
> *Subject:* [QE-users] Query for skip_type and equiv_type for DFT+U+V
>
> Dear Dr. Iurii (😊),
>
> The ATOMIC_POSITIONS cart of my structure (ferrimagnetic system with ntyp
> = 3 ) is
>
> ATOMIC_POSITIONS (crystal)
> Fe1           0.0000000000       -0.0000000000       -0.0000000000 (four
> times)
> Fe2           0.3749993721        0.3749993349        0.3750019210 (two
> times)
> O             0.2454868415        0.2454868399        0.2454949640 (eight
> times)
>
> Previously, based on ATOMIC_SPECIES cart, I defined my Hubbard tag as below
>
>   Hubbard_V(1,1,1) = 1.d-8
>   Hubbard_V(2,2,1) = 1.d-8
>   Hubbard_V(3,3,1) = 1.d-8
>
> In the hp output file, I saw that only one  Fe1 atom was perturbed.
>
> Then I defined below Hubbard tags according to ATOMIC_POSITIONS cart as
>
>   Hubbard_V(1,1,1) = 1.d-8
>   Hubbard_V(5,5,1) = 1.d-8
>   Hubbard_V(7,7,1) = 1.d-8
>
> which perturbed four atoms
>
>         1      Fe1    55.8450   tau( 1) = (  0.00000  0.00000  0.00000  )
>         4      Fe1    55.8450   tau( 4) = (  1.75000  1.01036  0.40825  )
>         5      Fe2    55.8450   tau( 5) = (  0.75000  0.43301  0.30619  )
>         7      O      15.9994   tau( 7) = (  0.49098  0.28347  0.20045  )
>
> As all Fe will have the same Hubbard parameter (as reported in the
> literature for the same system), I would like to skip the perturbation for
> atom Fe1(4) and Fe2(5).
>
> Is it okay if I do so?
>
> To skip the perturbation for Fe1(4) and Fe2(5), I have updated below tags
> in my hp input file:
>
> skip_type(1)=.true.
> skip_type(2)=.true.
> equiv_type(1)=1
> equiv_type(2)=1
> disable_type_analysis=.true.,
>
> Could you please correct me if this modification is correct or not?
>
> Sorry for the list of questions. But I am sure, my these queries will be
> helpful for others too.
>
> Thanks and regards
>
> K C Bhamu
>
> Postdoctoral Fellow
> University of Ulsan
> South Korea
>
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