[Pw_forum] total energy for charged defects in semiconductors

[张满红]

Dear Mostafa Youssef,

 

  Thanks a lot!

 

Best Regards,

 

Manhong 

 

 





-----原始邮件-----
发件人: "Mostafa Youssef" <myoussef at mit.edu>
发送时间: 2015-10-23 04:18:56 (星期五)
收件人: "pw_forum at pwscf.org" <pw_forum at pwscf.org>
抄送:
主题: Re: [Pw_forum] total energy for charged defects in semiconductors


Dear  Manhong,

As far I know the incosistency of treating charged defects within PAW formalism discussed in  PHYSICAL REVIEW B 89, 045116 (2014) has not been resolved in any pseudopotential code. I  wish I can devote more time  to study this paper more carefully.

Regarding the second paper,  PHYSICAL REVIEW B 91, 024107 (2015), it suggests that the arbitrariness  in the reference of the electrostatic potential has a sizable effect on the pressure (stress) calculated by DFT codes for charged systems.  Figure 1 tells the whole story.  The authors suggested a method to correct for that given the bulk modulus (eleastic constants) and the deformation potential. of the host semiconductor.  However, the paper is of concern if you plan to do variable cell relaxation.  Most of the charged defects papers focus on fixed volume calculations claiming that this is a good way to represent dilute limit of defects. 

In summary, if you plan to do fixed volume calculations, the second paper should not be of concern  (roughly speaking).  Resolving the inconsistency of the first paper is to be implemented. To avoid it one might use all electron code.


M. Y.
MIT
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