[Wien] How to approximate the <I^2> value from wien2K

[Peter Blaha]

Thank's for the nice summary. It contains a lot of hints how to proceed 
and calculate the necessary quantitites.

It would be very valuable if one of the users who is interesting in 
these quantities contributes his scripts/modifications/workflow to make 
them generally available.

Peter Blaha

On 02/28/2018 06:06 AM, Gavin Abo wrote:
> As far as I know, WIEN2k still does not include a package to calculate 
> <I^2> [ 
> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14478.html 
> ].
> 
> For WIEN2k calculations, I have seen <I^2> calculated with the 
> Gaspari-Gyorffy formula [ https://doi.org/10.1016/j.jallcom.2017.09.299 ].
> 
> "We thank W. E. Pickett for sharing the RMTA code with us" [ 
> https://doi.org/10.1103/PhysRevB.74.184519 ]
> 
> However, I haven't seen Pickett's [ 
> http://physics.ucdavis.edu/people/faculty/warren-pickett ] RMTA code 
> available to the general public.
> 
> As I recall, the calculation might require that you modify yourself 
> atpar.f [ 
> http://wien.zeus.theochem.tuwien.ac.narkive.com/ffod74Mc/calculation-of-electron-phonon-coupling-constant 
> ].
> 
> On 2/27/2018 3:54 AM, pachineela rambabu wrote:
>> Dear Wien2k, the electron-phonon coupling can be calculated by using 
>> the formula
>>
>> *Lambda=(Eta)/(m<w^2>)*, Here Eta is Hopefield parameter and can be 
>> written as
>>
>> *Eta= N(Ef)*<I^2>*, Here N(Ef) is total density of states and <I^2> is 
>> the square of electron-phonon matrix element over fermi surface.
>>
>> By using some approximations <w^2> can be written as 0.5*(Theta D^2), 
>> here Theta D is Debye temperature. And m is average atomic mass
>> So the final formula will become as
>>
>> *Lambda=(N(Ef)*<I^2>)/(m*0.5*Theta D^2).*
>>
>> Here i am facing the problem how to approximate the <I^2> value from 
>> wien2K band structure calculations.
>>
>> Please suggest a solution.
>>
>>
>> -- 
>> *P. Rambabu*
>> PhD Scholor
>> Physics, IIT Hyderabad
>> Mobile: 9074508220.
> 
> 
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-- 

                                       P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/TC_Blaha
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