Hi Abbout,

Thanks for swift response.
Indeed, the kwant.wavefunction module gives me a complex number. I had been
working on probability (wavefunction squared) and had overlooked the phase
part. A noob mistake.

Appreciate your help!

Shivang

On Thu, Jun 7, 2018 at 11:53 AM Abbout Adel <[email protected]> wrote:

> Dear Shivang,
>
> To get the matrix Gamma you can do:
>
> sys            =  sys.finalized()
> lead_L       =  sys.leads[0]
> Sigma_L    =  lead_L.selfenergy(energy)
> Gamma_L  =  -2*imag(Sigma_L)
>
> You can find the details in this answer by Joseph [1].
> To get directly the transmission matrix t you can do:
> t=kwant.smatrix(sys,energy, *out_leads=[1]*, *in_leads=[0]*).data
>    #I suppose you have just two leads.
>
> Now, since your aim is to get the wave function, the module
> kwant.wavefunction gives you the wavefunction as a complex number (module
> and *phase*). So, your claim that you are unable to get the phase is
> confusing!
>
> I hope this helps.
> Adel
>
> [1]
> https://mailman-mail5.webfaction.com/pipermail/kwant-discuss/2015-May/000355.html
>
>
>
> Abbout Adel
>
> On Wed, Jun 6, 2018 at 11:53 PM, Shivang Agarwal <
> [email protected]> wrote:
>
>> Hello authors,
>>
>> I am trying to perform an eigenchannel analysis of a graphene nanoribbon.
>> For that I will be using the formula :
>> *T(E) = ГL(E)½ GC†(E) ГR(E) GC(E) ГL(E)½ *
>> where *ГL(E)* is the coupling matrix between the left lead and the
>> conductor, *GC(E)* is the greens function matrix of the conductor
>> (system) and '†' is the dagger operator. The equation is from the
>> following paper:
>> https://journals.aps.org/prb/pdf/10.1103/PhysRevB.73.075429
>>
>> (1) Now as far as I know, Kwant allows us to calculate transmission as a
>> number T(E). What I need for my code is 't' where Trace(t*†*t) = T(E).
>> Could somebody let me know how can I get the desired quantity 't'?. But I
>> don't know how I can get the coupling matrix *ГL(E) between the left (or
>> right) lead and the conductor*
>>
>> (2) Also, we know that t = *ГL(E)½ GC(E) ГR(E)½ .But I don't know how I
>> can get the coupling matrix ГL(E) between the left (or right) lead and the
>> conductor. Is it possible to get too?*
>>
>> *PS - My aim is to find the wavefunctions inside the nanoribbon (which
>> Kwant can do very conveniently) and also their phases! I have found the
>> wavefunctions but am unable to find their phases. If there's any other way
>> to find it that would also be extremely helpful.*
>>
>> *Any help would be greatly appreciated.*
>>
>> *Thanks and Regards,*
>> *Shivang Agarwal*
>> --
>> *Shivang Agarwal*
>> Junior Undergraduate
>> Discipline of Electrical Engineering
>> IIT Gandhinagar
>>
>> Contact: +91-9869321451
>>
>
>
>
> --
> Abbout Adel
>


-- 
*Shivang Agarwal*
Junior Undergraduate
Discipline of Electrical Engineering
IIT Gandhinagar

Contact: +91-9869321451

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