[QE-users] [SPAM] Re: Assistance with Convergence Issues of Surface Calculations

[Giuseppe Mattioli]

Dear Vinay Maithani
You have likely not checked your structure before running the  
calculation. This is 99% of times the source of convergence problems.  
I've opened your input file with xcrysden and the structure seems to  
be completely wrong (see attached screenshot).
HTH
Giuseppe

Quoting Vinay Maithani <vinaymaithani21 at kgpian.iitkgp.ac.in>:

> Dear Quantum ESPRESSO community,
>
> I hope this email finds you well.
>
> I am currently working on large band gap semiconductors and have
> encountered persistent difficulties in achieving convergence while
> calculating the surface properties of these materials. Below are the
> strategies I have attempted so far:
>
>    - *Mixing Beta:* Adjusted up to 0.1
>    - *Mixdim:* Increased to 24
>    - *Smearing:* Gaussian with degauss = 0.2
>    - *Nbnd:* Added a minimum of 20% more than the number of Kohn-Sham states
>    - *Ecutwfc:* Increased from 50 Ry to 70 Ry
>    - *Ecutrho:* Set to 8 times Ecutwfc
>    - *Electron Max Step:* Extended to 2000 steps
>
> Despite these efforts, my calculations still fail to converge, returning
> the error:
> *“Convergence NOT achieved after *** iterations: stopping.”*
>
> I am using norm-conserving pseudopotentials and have applied dipole
> corrections, but the issue persists. I have attached the input and output
> files, along with the plot of potential data obtained via pp.x
> (plot_num=11) and averaged in the xy-plane where a discontinuity occurs in
> the vacuum region, available here: Google Drive link
> <https://drive.google.com/drive/folders/1HoSFk11TMN4qAo8jZoSvyEymK92xGu2r?usp=drive_link>
> .
>
> I would greatly appreciate any insights or suggestions you may have to help
> resolve this problem.
>
> Thank you for your time and guidance.
>
> Best regards,
> Vinay Maithani
> PhD Candidate, IIT Kharagpur
> vinaymaithani21 at kgpian.iitkgp.ac.in



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>
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