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QuantumATK => General Questions and Answers => Topic started by: qiuminz on February 21, 2019, 14:24

Title: The spin magnetic tunnel junction cant get converged
Post by: qiuminz on February 21, 2019, 14:24

Dear  Quantumwise staffs:
  I  calculated  a magnetic tunnel junction  with exchange correlation SGGA-PBE ,but  I cant get  converged.  the best  result  is  dE and dH can reduce to  10-3.
I  have  tried all  methods  in  the convergence  guide but failed ,   and  all  pseudo potential  are tested  ,but it  does not work , could  you  please  help me ?  thank  you 
  my log file is over 400k  I cant post it

Title: Re: The spin magnetic tunnel junction cant get converged
Post by: Ulrik G. Vej-Hansen on February 21, 2019, 16:21

Please see also the new document about convergence of this kind of system: https://docs.quantumatk.com/technicalnotes/spin_polarized_negf_convergence_guide/spin_polarized_negf_convergence_guide.html

Title: Re: The spin magnetic tunnel junction cant get converged
Post by: qiuminz on February 22, 2019, 08:54

I have tried  the method in this guide,but the results are worse than before .I dont know why the bad concergence happen.

Title: Re: The spin magnetic tunnel junction cant get converged
Post by: Petr Khomyakov on February 22, 2019, 11:07

Did you also look at these guidelines https://docs.quantumatk.com/technicalnotes/negf_convergence_guide/negf_convergence_guide.html#negf-convergence-guide?

Title: Re: The spin magnetic tunnel junction cant get converged
Post by: qiuminz on February 22, 2019, 12:01

yes  i did  ,

Title: Re: The spin magnetic tunnel junction cant get converged
Post by: Petr Khomyakov on February 22, 2019, 15:45

Try to increase the central region size of your device, see the script enclosed.

Title: Re: The spin magnetic tunnel junction cant get converged
Post by: qiuminz on February 23, 2019, 11:49

the script doesnt work  ,the result is similar to before . thank  you anywhere

Title: Re: The spin magnetic tunnel junction cant get converged
Post by: Anders Blom on April 19, 2019, 21:12

I would try to set the scaled spins closer to their expected values based on a bulk calculations

Title: Re: The spin magnetic tunnel junction cant get converged
Post by: qiuminz on April 20, 2019, 07:08

Thank you for your reply :)