[Pw_forum] relaxation of doped system

[Giuseppe Mattioli]

Dear Yao-Hong
It seems that you are working in a very accurate way. I would only say that (maybe) d metals such as Cu hosted in sp semiconductors could benefit of a 
DFT+U treatment, but it is only my biased suggestion! Is it is the scf of the Cu-doped system that does not converge, or is it the BFGS?
Best Wishes
Giuseppe

On Tuesday, May 03, 2016 12:12:23 PM n16031320 wrote:
> Dear Giuseppe:
> 
> Thanks for your response, I use Ver.5.3.0 of QE and GGA in the form of PBE.
> 
> About the type of pseudopotential, I use PAW from THEOS, according to the website it said that PAW type is widely tested and no error is reported.
> 
> I study some paper which is experiment, they dope with Ag and the percentage up to 7%, so I think 6.25% may be ok.
> 
> I studied the paper which is about experiment, it is said that SnSe doped with Al, Pb and Cu for 2%,respectively, don't change lattice parameter too
> much,
> 
> so I decided to do the relax calculation instead of vc-relax first for doped with Pb and Al for 6.25%, and the result show that the position of
> atoms don't change too mush,
> 
> then I check the total force is <0.0004 , I think the result of relaxation is reasonable. 
> 
> First I use 12 processors for the vc-relax calculation, now I use 48 processors for the relax calculation, 
> 
> the relax calculation for the doped with Al and Pb for 6.25% is done, but doped with Cu for 6.25% is still running, maybe 6.25% is too large for
> Cu? 
> 
> Also I will try to dope with lower percent too.
> 
> And what things I should pay attention to, any advice? Thanks!
> 
> Regards
> 
> Yao-Hong Huang
> 
> --
> 
> Graduate student
> 
> Department of Mechanical Engineering
> 
> National Cheng Kung University
> 
> Tainan, Taiwan

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   Giuseppe Mattioli                            
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