[QE-users] non-convergency of DFPT+U calculation

Merlin Meheut merlin.meheut at gmail.com
Tue Feb 18 17:21:46 CET 2020


Hi Iurii,

First thank you very much for this remark, I did not know that one could
not use tot_magnetization and starting_magnetization together. Indeed, this
is reported in the Documentation INPUT_PW.def.
At this point, however, I don't see how to make an input for an
antiferromagnetic insulating material (which is the goal here). Because
with this input, the state is non magnetic:

&system
    ibrav =8, celldm(1)=9.107535, celldm(2)=2.17425,
    celldm(3)=1.263056,
    nat =28, ntyp = 4, ecutwfc =80.0, ecutrho = 320.0,
    nspin=2,  tot_magnetization=0,
     lda_plus_u = .true., U_projection_type = 'atomic',
      Hubbard_U(1)=2.4, Hubbard_U(2)=2.6, ! valeurs Yu et al 2013 =2.4/2.6
/&end

And if you use this input:

&system
    ibrav =8, celldm(1)=9.107535, celldm(2)=2.17425,
    celldm(3)=1.263056,
    nat =28, ntyp = 4, ecutwfc =${a}.0, ecutrho = ${b}.0,
    nspin=2,
     starting_magnetization(1)=0.5, starting_magnetization(2)=-0.5,
    lda_plus_u = .true., U_projection_type = 'atomic',
    Hubbard_U(1)=2.5, Hubbard_U(2)=2.5,
/&end

,you  have an error message:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     Error in routine iosys (1):
     fixed occupations and lsda need tot_magnetization

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

So as you say, using starting_magnetization imposes using smearing. But if
I am correct, smearing means that your material is metallic, and therefore
you cannot compute dielectric quantities or effective charges with phonon.
Actually, in the INPUT_PW.def file, the word "antiferromagnetic" is only
present once, in the "starting_magnetization" definitions. Does that mean
that magnetic insulators cannot be treated by Quantum Espresso?

Would you have any hint as to how to extract myself from such a dead end?

Thanks again for your help,

Greetings,

Merlin

Le dim. 16 févr. 2020 à 23:11, Timrov Iurii <iurii.timrov at epfl.ch> a écrit :

> Dear Merlin,
>
>
> In your input for the PW calculation you have:
>
>
> > tot_magnetization=0,
> >     starting_magnetization(1)=0.5, starting_magnetization(2)=-0.5
>
>
> tot_magnetization and starting_magnetization must not be used together
> (please check the documentation). Moreover, starting_magnetization must be
> used with occupations='smearing', but I do not see smearing in your input.
> Is the ground state metallic or insulating?
>
>
> How many representations do you have in total? And only #23 diverges?
>
>
> Not sure this will help, but you may try to use dual = ecutrho/ecutwfc =
> 12, with ecutwfc=80 Ry.
>
>
> > Si   27.9769  Si.pz2.UPF
> >  O    15.9949   O.pz.UPF
>
>
> I do not know what are these pseudos, and how good/bad are they. You can
> try to check the SSSP library.
>
>
> >  Fe1  55.9349  Fe.pz-n-rrkjus_psl.1.0.0.UPF
> >   Fe2  55.9349   Fe.pz-n-rrkjus_psl.1.0.0.UPF
>
>
> Also for these I would check the SSSP library.
>
>
> Greetings,
>
> Iurii
>
>
> --
> Dr. Iurii Timrov
> Postdoctoral Researcher
> STI - IMX - THEOS and NCCR - MARVEL
> 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
> Merlin Meheut <merlin.meheut at gmail.com>
> *Sent:* Sunday, February 16, 2020 9:22:57 PM
> *To:* Quantum Espresso users Forum
> *Subject:* [QE-users] non-convergency of DFPT+U calculation
>
> Dear PWSCF users,
>
> I am trying to realize a phonon calculation (at gamma) with +U on fayalite
> (olivine structure Fe2SiO4) with anti-ferromagnetic configuration , and
> whether the calculation goes fine without +U, I have one representation
> (#23) that systematically fails to converge when I add a +U. I tried
> several values for the +U (0.5, 2.5, 4), several functionals (PZ, PBE), but
> the result is always the same. I have used QE versions 6.4 and 6.4.1 on two
> different computing centers . Would you have any idea about the reasons for
> such a failure? I am specifically worried by one output message: "Atomic
> wfc used for the DFT+U projector are NOT orthogonalized", but I don't know
> how to fix that.
>
> Here are examples of my scf and ph inputs, and the failing ph output:
>
> scf:
>  &control
>        calculation = 'scf',
>     (...)
>     tprnfor        = .true.,
>     tstress        = .true.,
> /&end
> &system
>     ibrav =0, celldm(1)=9.107535,
>     nat =28, ntyp = 4, ecutwfc =80.0, ecutrho = 320.0,
>     nspin=2,   tot_magnetization=0,
>     starting_magnetization(1)=0.5, starting_magnetization(2)=-0.5,
>      lda_plus_u = .true., U_projection_type = 'atomic',
>       Hubbard_U(1)=2.4, Hubbard_U(2)=2.6
> /&end
>  &electrons
>    electron_maxstep = 150,
>           conv_thr = 1.d-11,
>        mixing_mode = 'plain',
>        startingwfc = 'atomic',
>        mixing_beta = 0.3,
> /&end
> ATOMIC_SPECIES
>   Fe1  55.9349  Fe.pz-n-rrkjus_psl.1.0.0.UPF
>   Fe2  55.9349   Fe.pz-n-rrkjus_psl.1.0.0.UPF
>   Si   27.9769  Si.pz2.UPF
>   O    15.9949   O.pz.UPF
> (...)
>
> ph input:
>  &inputph
>    amass(1)=55.9349,
>    amass(2)=55.9349,
>    amass(3)=27.9769,
>    amass(4)=15.9949,
>    alpha_mix(1) = 0.5,
>    ! ldisp=.true., nq1=2, nq2=2, nq3=2,
>    tr2_ph =  1.0D-17,
>    prefix='FAYA2',
>    fildyn='mat.$PREFIX',
>    lraman=.false.,
>    epsil =.false.,
>    trans =.true.,
>    zue = .false.,
>    zeu= .false.,
>    start_irr=23,
>    last_irr=23,
>    outdir         ='./',
> /&end
> 0.0 0.0 0.0
>
> ph output:
>  Representation # 23 mode #  23
>
>      Self-consistent Calculation
>
>       iter #   1 total cpu time :    58.7 secs   av.it.:   8.5
>       thresh= 1.000E-02 alpha_mix =  0.500 |ddv_scf|^2 =  1.045E-06
>
>       iter #   2 total cpu time :    62.9 secs   av.it.:  23.0
>       thresh= 1.022E-04 alpha_mix =  0.500 |ddv_scf|^2 =  2.668E-04
>
>       iter #   3 total cpu time :    66.4 secs   av.it.:  17.5
>       thresh= 1.633E-03 alpha_mix =  0.500 |ddv_scf|^2 =  3.033E-03
>
>       iter #   4 total cpu time :    69.0 secs   av.it.:  11.0
>       thresh= 5.508E-03 alpha_mix =  0.500 |ddv_scf|^2 =  5.602E-02
>
>       iter #   5 total cpu time :    73.0 secs   av.it.:  15.5
>       thresh= 1.000E-02 alpha_mix =  0.500 |ddv_scf|^2 =  1.238E+00
>
>       iter #   6 total cpu time :    76.7 secs   av.it.:  19.5
>       thresh= 1.000E-02 alpha_mix =  0.500 |ddv_scf|^2 =  2.841E+01
>
>       iter #   7 total cpu time :    80.9 secs   av.it.:  23.0
>       thresh= 1.000E-02 alpha_mix =  0.500 |ddv_scf|^2 =  6.534E+02
>
>       iter #   8 total cpu time :    85.3 secs   av.it.:  24.5
>       thresh= 1.000E-02 alpha_mix =  0.500 |ddv_scf|^2 =  1.446E+04
>
>       iter #   9 total cpu time :    90.1 secs   av.it.:  27.5
>       thresh= 1.000E-02 alpha_mix =  0.500 |ddv_scf|^2 =  3.214E+05
>
>       iter #  10 total cpu time :    95.5 secs   av.it.:  30.0
>       thresh= 1.000E-02 alpha_mix =  0.500 |ddv_scf|^2 =  7.200E+06
>
> (.....)
>
> Thank you in advance for your help! Feel free to ask for any further
> calculation details.
>
> Regards,
> --
> Merlin Méheut
> adresse labo:
> GET - OMP   - Université Paul Sabatier
> 14 avenue Edouard Belin
> 31400 Toulouse
> FRANCE
> tel: (+33) 5 61 33 26 17
>
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-- 
Merlin Méheut
adresse labo:
GET - OMP   - Université Paul Sabatier
14 avenue Edouard Belin
31400 Toulouse
FRANCE
tel: (+33) 5 61 33 26 17
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