Hi Shivang,

The transmitted wave function  transmitted in the mode m (and coming from the mode n) is:

t_mn exp(i k_m).

Since you have the transmitted amplitudes and the wavenumbers k_m, you have everything for your request.


I hope this helps.
Adel

  

On Fri, Jun 8, 2018 at 11:09 PM, Shivang Agarwal <shivang.agarwal@iitgn.ac.in> wrote:
Hi,

I had one more query. Would it be possible to calculate and plot the magnitude and phase of the complex wave function of each transmission mode separately?

Regards,
Shivang

On Thu, Jun 7, 2018 at 8:29 PM Shivang Agarwal <shivang.agarwal@iitgn.ac.in> wrote:
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 <abbout.adel@gmail.com> 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


On Wed, Jun 6, 2018 at 11:53 PM, Shivang Agarwal <shivang.agarwal@iitgn.ac.in> 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(tt) = 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


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

Contact: +91-9869321451



--
Abbout Adel