Dear all,
To test kwant as a beginner  I wanted to solve a CIP GMR system (not CPP).
Usual config. is 2 FMs separated by a NM; however because it is CIP, then the 
leads are partially connected to the 3 layers
My system extends from the quantum wire problem adding Pauli matrices and the 
conservation law sigma_z
I added impurities using a random function; however, my output sometimes shows 
a larger conductance for the antiparallel case (rather than the parallel one). 
No integration involved, simple conductance calculation using:  
"smatrix.transmission(1, 0))". 

>From a code perspective, my only concern is on the leads, for instance I have 
>for one ferromagnet:
leftlead[(lat(0, j) for j in range(W))] = Jxc * (sigma_x*mx + sigma_y*my + 
sigma_z*mz )

I do not add impurities on the leads. the 4t term is not taken as i shifted the 
bandwidth. Is this a good "oversimplified approach?

>From a kwant perspective,
As I said, sometimes the AP case is larger than the P config. Because of this I 
performed a random distribution average over 10000 loops and my result shows 
that in 25% of the cases AP is larger than P.  Why it is not possible to get a 
solution to this system with low error? Is it because the quantum wire 
conductance  problem is too simple to give proper results for CIP GMR?  Shall I 
avoid using the conductance and focus instead on current out of equlibrium? Or 
CIP-GMR has particular constraints that I'm omitting in Kwant. 
Thanks a lot for a response...

Reply via email to