[QE-users] non-convergency of DFPT+U calculation
Timrov Iurii
iurii.timrov at epfl.ch
Wed Feb 19 10:05:01 CET 2020
Dear Merlin,
Total magnetization must be zero for an antiferromagnetic insulator. Hence, some deviation from zero that you obtain is probably a numerical noise (I would check the convergence of the results: reduce conv_thr, increase the size of the k mesh, etc., and relax well the structure).
> If I wanted to be closer to the smearing calculation, I would have to consider nocolin=.true., is that right?
DFPT+U with noncolin=.true. is not implemented.
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: Wednesday, February 19, 2020 12:38:08 AM
To: Quantum ESPRESSO users Forum
Subject: Re: [QE-users] non-convergency of DFPT+U calculation
Dear Iurii,
Thank you again for your help! So far, the Example02 seems quite clear to me, although it will take me some time to apply it to my system and check that everything is working. One quick question, though: in my case, the "total magnetization" obtained from the first calculation (with smearing) is non-zero and non-integer: "total magnetization = -0.63 Bohr mag/cell" (which makes sense since I have two different sites). As I understand it, for the second calculation, the variable tot_magnetization should be integer, so I can only take it equal to 0 or 1 here (I tried with 0, I don't know which is better). If I wanted to be closer to the smearing calculation, I would have to consider nocolin=.true., is that right?
Greetings,
Merlin
Le mar. 18 févr. 2020 à 17:32, Timrov Iurii <iurii.timrov at epfl.ch<mailto:iurii.timrov at epfl.ch>> a écrit :
Dear Merlin,
> Does that mean that magnetic insulators cannot be treated by Quantum Espresso?
It is possible to model magnetic insulators in Quantum ESPRESSO. I am using the procedure described in q-e-qe-6.5/HP/examples/example02/README. If the description in README file is not clear enough, please let me know.
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<mailto:users-bounces at lists.quantum-espresso.org>> on behalf of Merlin Meheut <merlin.meheut at gmail.com<mailto:merlin.meheut at gmail.com>>
Sent: Tuesday, February 18, 2020 5:21:46 PM
To: Quantum ESPRESSO users Forum
Subject: Re: [QE-users] non-convergency of DFPT+U calculation
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<mailto: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<mailto:users-bounces at lists.quantum-espresso.org>> on behalf of Merlin Meheut <merlin.meheut at gmail.com<mailto: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<http://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<http://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<http://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<http://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<http://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<http://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<http://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<http://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<http://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<http://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
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>)
users mailing list users at lists.quantum-espresso.org<mailto:users at lists.quantum-espresso.org>
https://lists.quantum-espresso.org/mailman/listinfo/users
--
Merlin Méheut
adresse labo:
GET - OMP - Université Paul Sabatier
14 avenue Edouard Belin
31400 Toulouse
FRANCE
tel: (+33) 5 61 33 26 17
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>)
users mailing list users at lists.quantum-espresso.org<mailto:users at lists.quantum-espresso.org>
https://lists.quantum-espresso.org/mailman/listinfo/users
--
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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