[QE-users] Problem in vc-relax calculation with Hubbard U in magnetic system

[Thomas Brumme]

Hi Iurii,


I'm working with Vivek on the structure - one question I would have is why is QE different from VASP? (and which solution is correct?)

In VASP the relaxation is not restricted and since both codes use more or less the same theory, the difference might come from some
details in the implementation of +U or from some things related to the pseudo. Do you have any feeling/idea if changing to a different
pseudo or something different concerning +U might influence the relaxation?


Kind regards


Thomas

--
Dr. rer. nat. Thomas Brumme
Theoretical chemistry
TU Dresden - KOE / 103
Bergstr. 66c
01069 Dresden

Tel:  +49 (0)351 463 40844

email: thomas.brumme at tu-dresden.de


________________________________
Von: users <users-bounces at lists.quantum-espresso.org> im Auftrag von Iurii TIMROV via users <users at lists.quantum-espresso.org>
Gesendet: Sonntag, 27. November 2022 12:17
An: Vivekanand Shukla; Quantum ESPRESSO users Forum
Betreff: Re: [QE-users] Problem in vc-relax calculation with Hubbard U in magnetic system


> The output structure does not hold the monoclinic symmetry; Hubbard U should help it achieve that. However, I do not get it despite using any Hubbard U.


Maybe you can try to impose the monoclinic symmetry (ibrav = 12 or -12), apply +U, and use cell_dofree = "ibrav" during the vc-relax calculation.


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: Vivekanand Shukla <vivekanand.shukla at chalmers.se>
Sent: Friday, November 25, 2022 5:30:59 PM
To: Iurii TIMROV; Quantum ESPRESSO users Forum
Subject: Re: [QE-users] Problem in vc-relax calculation with Hubbard U in magnetic system


Dear Iurii,


Thank you for the reference links. I followed them and ran some tests. It works with U prediction. However, with CoPS3, I wonder whether even Hubbard's inclusion is working.


So there is some change. Is it not what you expect?


Problem: Without Hubbard U inclusion lattice parameter comes {a ≠ sqrt(3)*b}, but with the inclusion of U, it should be corrected to more like {a = sqrt(3)*b}. According to the literature.


The output structure does not hold the monoclinic symmetry; Hubbard U should help it achieve that. However, I do not get it despite using any Hubbard U.


I also ran calculations with higher convergence criteria but ended up with similar lattice parameters. I am now running a calculation with ibrav= -12, but I am wondering if it is the right approach in this system.


Regards

Vivek

TU Dresden


________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of Iurii TIMROV via users <users at lists.quantum-espresso.org>
Sent: Friday, November 25, 2022 5:11:30 PM
To: users at lists.quantum-espresso.org
Subject: Re: [QE-users] Problem in vc-relax calculation with Hubbard U in magnetic system


Dear Vivek,


> I want to predict the self-consistent Hubbard parameter using HP code.


Please have a look here:

https://www.materialscloud.org/learn/sections/tctKdH/advanced-quantum-espresso-tutorial-2022


> ...but the structure remains the same.


>From your input and output files I see this:


OLD

CELL_PARAMETERS (angstrom)
  5.8969998360         0.0000000000         0.0000000000
  0.0000000000        10.2159996033         0.0000000000
 -1.9672647655         0.0000000000         6.3670060311


NEW

CELL_PARAMETERS (angstrom)
   5.771620672   0.000000000   0.036554788
   0.000000000  10.142807293   0.000000000
  -1.885622677   0.000000000   6.187226171


So there is some change. It is not what you expect?


> conv_thr =  1.d-6


Try 1.d-10 or even smaller


> forc_conv_thr  = 1.d-3


Try forc_conv_thr  = 1.d-4 or 1.d-5

and

etot_conv_thr = 1.d-5 or 1.d-6


Have a look also here:

https://www.materialscloud.org/work/tools/qeinputgenerator


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 Vivekanand Shukla <vivekanand.shukla at chalmers.se>
Sent: Friday, November 25, 2022 4:34:20 PM
To: users at lists.quantum-espresso.org
Subject: [QE-users] Problem in vc-relax calculation with Hubbard U in magnetic system


Dear all,

I am trying to run a vc-relax calculation for CoPS3 in bulk with the Hubbard U parameter. CoPS3 results in off-lattice parameters without Hubbard U. I checked it with VASP, and it seems realistic. However, in QE, the Hubbard U parameter has no effect on the lattice parameter. It remains off with or without U. I can see the Hubbard effect in forces in the output file, but it does not reflect on the lattice parameter in QE output.

I want to predict the self-consistent Hubbard parameter using HP code. It does not make sense if I do not get the inclusion of the U parameter right in the first place. I used QE versions 6.4.1, 6.7, and 7.0 and various convergence strategies, but the structure remains the same.

Could anyone please suggest anything wrong with the calculation? Please find one of the input and output files in the attached link.


https://cloudstore.zih.tu-dresden.de/index.php/s/8cCf3N8qd3swW5d

[https://cloudstore.zih.tu-dresden.de/core/img/favicon-fb.png]<https://cloudstore.zih.tu-dresden.de/index.php/s/8cCf3N8qd3swW5d>

Cloudstore<https://cloudstore.zih.tu-dresden.de/index.php/s/8cCf3N8qd3swW5d>
cloudstore.zih.tu-dresden.de
Cloudstore - based on <a href="https://nextcloud.com/\">Nextcloud</a>


Sincerely
Vivek
Postdoctoral Researcher
Technical University Dresden

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