[Pw_forum] Re: whether PWSCF can calculte the transport spectral

[Malgorzata Wierzbowska]

On Tue, 29 Aug 2006, Steven Dixon wrote:

> Dear Gosia:
> Thank you for your reply.
> I know that group velocity can be calculated from the
> derivative of the
> band energy respect to kx, ky, kz. Then the efficiency
> factor can be
> calculated, then a2F. I have read some codes about
> calculation of the
> spectral function. But  I still don't know how to
> calculate the efficiency
> properly and add it to the transport spectral
> function. Can you help me
> to modify that codes, and sent it to me?
>

   Let us talk about the code between us and we will
   make it public at the end.

> Another question: If the structure is anisotropy.
> Whether the electrical
> conductivity tensor can be calculate use this
> theory/PWcodes?
>

   Yes. There is a  vector k-dependence.

   Gosia



> Thanks in advance and best wishes
>
> Steven Dixon
>
>>> Dear all:
>>> I am a new user of PWSCF. I write my questions as
>> follows:
>>> In the PHYSICAL REVIEW B, VOLUME 57, NUMBER 18
>> 11276, it introduce the
>>> electron-phonon intreaction spectral function of
>> superconductor and the transport
>>> spectral function, and it said the
>> efficiency factor is the only difference
>> between
>>> these two functions. I know that PWSCF can
>> calculte the electron-phonon intreaction
>>> spectral function, I want to know whether PWSCF
>> can calculte the transport
>>> spectral function.
>>>
>>> Steven Dixon
>>>
>>
>>    No pwscf does not compute transport a2F. In order
>> to do this you may
>> compare equations 4,5, 8 and 9 from the paper you
>> cite. Then you can modify
>> the code in file PH/elphon.f90, subroutine elphsum.
>> You grep on "la2F" and you go to the place where the
>> phonon
>> linewidth "gamma" is calculated (around line 600).
>> Gamma is given as a function of the mode "nu" and
>> the broadening "isig".
>>
>> Since the efficiency factor depends both on mode and
>> on k-point,
>> you have to start your changes where gamma depends
>> on k, in objects: gf, ctemp, noint, g3.
>>
>> Do you use option la2F=.true., or you do it in older
>> fashion?
>>
>> Please let me know whether you see what needs to be
>> done.
>> If not I will change this part.
>>
>>   Have fun,
>>    Gosia
>
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