Dear Giuseppe,
> Out of further curiosity, a few years ago there has been a fuss over
> the "global U" approach of the pseudo-hybrid ACBN0 functional, which
> had been tested on ZnO among other cases (Phys. Rev. X 2015, 5, 011006).
> It seems that the ACBN0 implementation "didn't hit the market"... Is
> it an active project?
As far as I know, it is still active and used in different groups. To the best of my knowledge, ACBN0 is not implemented in Quantum ESPRESSO (at least in the public version). But it is implemented in other codes e.g. Octopus.
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 Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
Sent: Thursday, June 18, 2020 12:24:22 PM
To: Quantum ESPRESSO users Forum
Subject: Re: [QE-users] Problems with hp.x
Out of further curiosity, a few years ago there has been a fuss over
the "global U" approach of the pseudo-hybrid ACBN0 functional, which
had been tested on ZnO among other cases (Phys. Rev. X 2015, 5, 011006).
It seems that the ACBN0 implementation "didn't hit the market"... Is
it an active project?
Best
Giuseppe
Quoting Timrov Iurii <iurii.timrov at epfl.ch>:
>> ...because the 2 shell is fully occupied
>
>
> because the d shell is fully occupied.
>
>
> Sorry!
>
>
> Iurii
>
>
> ________________________________
> From: users <users-bounces at lists.quantum-espresso.org> on behalf of
> Timrov Iurii <iurii.timrov at epfl.ch>
> Sent: Thursday, June 18, 2020 10:08:19 AM
> To: Quantum ESPRESSO users Forum
> Subject: Re: [QE-users] Problems with hp.x
>
>
>> Since it's Cu(I) isn't
>> that a closed shell, a d10 system aswell? I was wondering why the
>> linear-response theory works in this case but not for Zn2+.
>
>
> Indeed, Cu2O has the same problem as ZnO, because the 2 shell is
> fully occupied. In our paper, for Cu2O we obtained U for Cu-3d
> states of 11.3 eV - this is from a one-shot calculation. This value
> of U is already large. If U is computed in a self-consistent way,
> then at 2nd, 3rd, and next iterations U for Cu-3d states will be
> larger and larger. This is because the d shell is full and it is
> pushed deeper and deeper in energy with increasing U, and the
> linear-response theory gives larger and larger values of U at the
> subsequent iterations. I realized quite late that Cu2O is not really
> a good "demonstrator" for our PRB 2018 paper - however, on the other
> hand, still it is OK just for the sake of benchmarking DFPT versus
> the finite-difference supercell approach of PRB 71, 035105 (2005).
>
>
> Concerning the question why in the one-shot calculation Cu-3d (in
> Cu2O) has U of ~11 eV and Zn-3d (in ZnO) has U of ~20 eV, is because
> Zn-3d states are deeper in energy than Cu-3d states (at the DFT
> level - which is typically the starting point for the HP calculation).
>
>
> HTH
>
>
> 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
> dv009200 at fh-muenster.de <dv009200 at fh-muenster.de>
> Sent: Wednesday, June 17, 2020 11:42:28 PM
> To: Quantum ESPRESSO users Forum
> Subject: Re: [QE-users] Problems with hp.x
>
> Thanks again thats for sure very helpful.
>
> Just out of curiosity I may have one more question: In the paper thats the
> basis of the hp.x code (I. Timrov, N. Marzari, M. Cococcioni, Phys. Rev. B
> 98, 085127, DOI:10.1103/PhysRevB.98.085127) the Hubbard U parameter of
> Cu2O is computed by the linear-response theory. Since it's Cu(I) isn't
> that a closed shell, a d10 system aswell? I was wondering why the
> linear-response theory works in this case but not for Zn2+.
>
> Best regards
>
> Dominik Voigt
>
> Dominik Voigt
> PhD Student University of Applied Sciences Münster
> Department of Physical Chemistry
>
>
>
>>
>> Dear Dominik
>>
>>> the method you suggested Giuseppe. I don't quite know whats the 'right'
>>> distance between the valence band and the d-band? Can I use experimental
>>> data from xps/ups spectra for that matter or do you have other
>>> suggestions?
>>
>> Yes, it is actually what I did with ZnO. As I remarked in my previous
>> message, it is going to work well if you apply the correction also to
>> the S 3p shell, in a DFT+U(Zn,S) fashion. In wurtzite ZnO the strong
>> curvature of the Zn 4s conduction band is such that the CB is
>> substantially free from delocalization error and it is a good absolute
>> reference. If you know the position of the Fermi level (which can
>> depend on intrinsic defects in real samples) with respect to the CB,
>> then you can reasonably estimate the position of the Zn 3d band.
>> I hope I've not added entropy...
>> Best
>> Giuseppe
>>
>> Quoting dv009200 at fh-muenster.de:
>>
>>> Thanks all for the helpful comments and interesting papers. I'm fine
>>> correcting the delocalization error of the Zn 3d states 'semiempirical'
>>> by
>>> the method you suggested Giuseppe. I don't quite know whats the 'right'
>>> distance between the valence band and the d-band? Can I use experimental
>>> data from xps/ups spectra for that matter or do you have other
>>> suggestions?
>>>
>>> Best regards
>>>
>>> Dominik Voigt
>>>
>>> Dominik Voigt
>>> PhD Student University of Applied Sciences Münster
>>> Department of Physical Chemistry
>>>
>>>
>>>
>>>> Dear All,
>>>>
>>>>
>>>> Giuseppe is right, this is a limitation of the current implementation
>>>> of
>>>> the linear-response theory to compute Hubbard parameters for
>>>> closed-shell
>>>> systems (like ZnO, ZnS, etc.). This "limitation" is known, and there is
>>>> some comment about this in q-e/HP/Doc/README. Please check this paper
>>>> for
>>>> more details:
>>>> <https://aip.scitation.org/doi/10.1063/1.4869718>
>>>>
>>>> https://aip.scitation.org/doi/10.1063/1.4869718
>>>>
>>>>
>>>> The developers of the HP code are planning to investigate this issue in
>>>> more detail, and hopefully we will come out with some solution in the
>>>> near
>>>> future.
>>>>
>>>>
>>>> Best regards,
>>>>
>>>> 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
>>>> Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
>>>> Sent: Monday, June 15, 2020 10:55:59 PM
>>>> To: Quantum ESPRESSO users Forum
>>>> Subject: Re: [QE-users] Problems with hp.x
>>>>
>>>>
>>>> Dear Dominik
>>>> I suppose that the problem is not in hp.x, but in the application of
>>>> the linear-response method itself to Zn(2+). Zn(2+) is a d10
>>>> transition metal, with the 3d band fully occupied. In ZnO, e.g., the
>>>> Zn 3d band is quite narrow and placed below the O 2p valence band, and
>>>> I suppose that the same holds for ZnS, with the Zn 3d band pushing up
>>>> the S 3p band. When you apply the LR method to Zn, you compute
>>>> quantities such as d(alpha)/dn, where alpha is the (small)
>>>> perturbation and n is the occupation number of d orbitals on site I
>>>> (see International Journal of Quantum Chemistry 2014, 114, 14 for
>>>> details). If the shell is full, then you can perturb whatever you want
>>>> but you will never obtain more than the full occupation of the shell
>>>> that you already have in the unperturbed system. This is likely the
>>>> reason for the crazy values of LR U you obtain. If you want to correct
>>>> the strong delocalization error of the Zn 3d narrow band within the
>>>> DFT+U formalism, then you must use a "semiempirical" approach,
>>>> choosing, e.g., the U value that places the Zn 3d shell at the correct
>>>> distance from the valence band maximum. In this case, I would
>>>> recommend the use of a second +U correction on the S 3p shell, which
>>>> should ensure a good recovery of the ZnS band gap. I've satisfactorily
>>>> used this scheme in the case of ZnO in several publications, from
>>>> which you may want to take inspiration (Adv. Energy Mater. 2014, 4,
>>>> 1301694).
>>>> HTH
>>>> Giuseppe
>>>>
>>>> Quoting dv009200 at fh-muenster.de:
>>>>
>>>>> Hello everyone,
>>>>>
>>>>> I'm trying to calculate the hubbard u parameter for Zn in Zinc sulfide
>>>>> (sphalerite structure) with the help of the hp.x code. The
>>>>> calculations
>>>>> terminate normally without any errors. The problem is that I get
>>>>> (presumably) way too high values for U that also won't converge (if I
>>>>> take
>>>>> the value I got from a one-shot calculation and plug it in the SCF
>>>>> input
>>>>> and then redo the HP calculation).
>>>>>
>>>>> For example in the first step I calculate a U = 75.7035 in the second
>>>>> iteration I get U = 804.2405 and in the third U = 30999.2684.
>>>>>
>>>>> This seems unreasonable considering that the calculations for the
>>>>> provided
>>>>> examples in the 'HP' folder work fine and converge fast without such a
>>>>> massive change to a certain value for U using the above described
>>>>> scheme.
>>>>>
>>>>> Has someone an idea what is causing this trouble in my system? I
>>>>> already
>>>>> tried different PPs, functionals, U_projection_type, thresholds and k
>>>>> and
>>>>> q point grids all without success.
>>>>>
>>>>> Below is my input for the scf and hp calculation
>>>>>
>>>>> SCF-input:
>>>>> &control
>>>>> calculation='scf'
>>>>> restart_mode='from_scratch',
>>>>> pseudo_dir = '/home/dominik/codes/QE6.5/pseudo/'
>>>>> outdir='/home/dominik/codes/QE6.5/tempdir/'
>>>>> prefix='zns'
>>>>> /
>>>>> &SYSTEM
>>>>> ibrav = 2
>>>>> celldm(1)=10.291937439
>>>>> nat = 2
>>>>> ntyp = 2
>>>>> ecutwfc = 60.0
>>>>> ecutrho= 720.0
>>>>> lda_plus_u = .true.
>>>>> lda_plus_u_kind = 0
>>>>> U_projection_type = 'atomic'
>>>>> Hubbard_U(1) = 1d-8
>>>>> /
>>>>> &electrons
>>>>> mixing_beta=0.7
>>>>> conv_thr=1d-15
>>>>> /
>>>>> ATOMIC_SPECIES
>>>>> Zn 65.39 Zn.pbe-dn-rrkjus_psl.0.2.2.UPF
>>>>> S 32.07 S.pbe-n-rrkjus_psl.0.1.UPF
>>>>> ATOMIC_POSITIONS {alat}
>>>>> Zn 0.000000 0.000000 0.000000
>>>>> S 0.250000 0.250000 0.250000
>>>>> K_POINTS automatic
>>>>> 12 12 12 0 0 0
>>>>>
>>>>>
>>>>> HP-input:
>>>>> &inputhp
>>>>> prefix='zns'
>>>>> outdir='/home/dominik/codes/QE6.5/tempdir/'
>>>>> nq1 = 2
>>>>> nq2 = 2
>>>>> nq3 = 2
>>>>> conv_thr_chi = 1.0d-10
>>>>> iverbosity =2
>>>>> /
>>>>>
>>>>>
>>>>> Best regards
>>>>>
>>>>>
>>>>> Dominik Voigt
>>>>>
>>>>> Dominik Voigt
>>>>> PhD Student University of Applied Sciences Münster
>>>>> Department of Physical Chemistry
>>>>>
>>>>> _______________________________________________
>>>>> Quantum ESPRESSO is supported by MaX
>>>>> (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>>>)
>>>>> users mailing list users at lists.quantum-espresso.org
>>>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>>>
>>>>
>>>>
>>>> GIUSEPPE MATTIOLI
>>>> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
>>>> Via Salaria Km 29,300 - C.P. 10
>>>> I-00015 - Monterotondo Scalo (RM)
>>>> Mob (*preferred*) +39 373 7305625
>>>> Tel + 39 06 90672342 - Fax +39 06 90672316
>>>> E-mail: <giuseppe.mattioli at ism.cnr.it>
>>>>
>>>> _______________________________________________
>>>> Quantum ESPRESSO is supported by MaX
>>>> (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>>>)
>>>> users mailing list users at lists.quantum-espresso.org
>>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>>> _______________________________________________
>>>> Quantum ESPRESSO is supported by MaX
>>>> (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>>)
>>>> users mailing list users at lists.quantum-espresso.org
>>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>>
>>>
>>> _______________________________________________
>>> Quantum ESPRESSO is supported by MaX
>>> (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>>)
>>> users mailing list users at lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>
>>
>>
>> GIUSEPPE MATTIOLI
>> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
>> Via Salaria Km 29,300 - C.P. 10
>> I-00015 - Monterotondo Scalo (RM)
>> Mob (*preferred*) +39 373 7305625
>> Tel + 39 06 90672342 - Fax +39 06 90672316
>> E-mail: <giuseppe.mattioli at ism.cnr.it>
>>
>> _______________________________________________
>> Quantum ESPRESSO is supported by MaX
>> (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>>)
>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
>
>
> _______________________________________________
> Quantum ESPRESSO is supported by MaX
> (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>>)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <giuseppe.mattioli at ism.cnr.it>
_______________________________________________
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
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