Reflectionless contacts
Hello everyone, I have defined two semiinfinite contacts in my system as follows:  def lead_shape(p): x, y, z = p return 10 < x < 10 and 6 < y < 6 and 0 < z < 30 sym_lead = kwant.TranslationalSymmetry(lattice.vec((6, 0, 0))) lead = kwant.Builder(sym_lead) lead[lattice.shape(lead_shape, (0, 0, 15))] = 0  Is there an easy way to calculate any reflections from the lead back into the conductor? I mean, ideally, I would like all electrons entering the contacts to stay there. Regards Eleni  Dr. Eleni Chatzikyriakou Computational Physics lab Aristotle University of Thessaloniki elchatz@auth.gr  tel:+30 2310 998109
Hi Eleni,
It's a hard problem, and usually we reduce reflection by creating a
smooth interface between the scattering region and the contact. As far
as measuring the quality of such interface goes, I think the most
practical approach is to replace the scattering region with another
lead with dispersion mimicking that of the scattering region as
closely as possible.
Best,
Anton
On Sun, Apr 22, 2018 at 12:13 PM,
Hello everyone,
I have defined two semiinfinite contacts in my system as follows:
 def lead_shape(p): x, y, z = p return 10 < x < 10 and 6 < y < 6 and 0 < z < 30
sym_lead = kwant.TranslationalSymmetry(lattice.vec((6, 0, 0))) lead = kwant.Builder(sym_lead) lead[lattice.shape(lead_shape, (0, 0, 15))] = 0 
Is there an easy way to calculate any reflections from the lead back into the conductor? I mean, ideally, I would like all electrons entering the contacts to stay there.
Regards
Eleni
 Dr. Eleni Chatzikyriakou Computational Physics lab Aristotle University of Thessaloniki elchatz@auth.gr  tel:+30 2310 998109
Hello Anton,
So, my contacts are exactly of the same structure and have the same TB
model defined as the scattering region.
I was more concerned about the semifiniteness of the leads, and
wanted to make sure that I was not just defining two finite regions at
the edges of the scattering region.
But from what I see leads actually do take shape functions and not
necessarily just translation vectors.
Regards,
Eleni
Quoting Anton Akhmerov
Hi Eleni,
It's a hard problem, and usually we reduce reflection by creating a smooth interface between the scattering region and the contact. As far as measuring the quality of such interface goes, I think the most practical approach is to replace the scattering region with another lead with dispersion mimicking that of the scattering region as closely as possible.
Best, Anton
On Sun, Apr 22, 2018 at 12:13 PM,
wrote: Hello everyone,
I have defined two semiinfinite contacts in my system as follows:
 def lead_shape(p): x, y, z = p return 10 < x < 10 and 6 < y < 6 and 0 < z < 30
sym_lead = kwant.TranslationalSymmetry(lattice.vec((6, 0, 0))) lead = kwant.Builder(sym_lead) lead[lattice.shape(lead_shape, (0, 0, 15))] = 0 
Is there an easy way to calculate any reflections from the lead back into the conductor? I mean, ideally, I would like all electrons entering the contacts to stay there.
Regards
Eleni
 Dr. Eleni Chatzikyriakou Computational Physics lab Aristotle University of Thessaloniki elchatz@auth.gr  tel:+30 2310 998109
 Dr. Eleni Chatzikyriakou Computational Physics lab Aristotle University of Thessaloniki elchatz@auth.gr  tel:+30 2310 998109
participants (2)

Anton Akhmerov

elchatz＠auth.gr