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

[Vivekanand Shukla]

Dear Iurri,



I tried with ibrav = 12, but it also ended up with a similar problem with the lattice. I have submitted another calculation with ibrav= -12 and cell_dofree = 'ibrav'.


If it works, I can use vc-relax with ibrav= -12 and cell_dofree= 'ibrav'  to calculate the Hubbard U parameter. Do you think this will be the right approach?


Sincerely

Vivek

________________________________
From: Iurii TIMROV <iurii.timrov at epfl.ch>
Sent: Sunday, November 27, 2022 12:17:36 PM
To: Vivekanand Shukla; Quantum ESPRESSO users Forum
Subject: 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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