Dear Michael,
 
  Thanks for your prompt response. That is exactly what I am now trying to achieve: make the lead by repeating only a portion of the scattering region, using the shape function to crop out the portion that I want; meanwhile the amorphous scattering region is defined within a single huge "lattice" with only one cell, containing the entire scattering region.

 But the periodicity of the lead would be much smaller than the size of the scattering region, and I would get the error that the lattice vectors of the scattering region is not commensurate with the periodicity (TranslationalSymmetry) of the leads. Am I missing something here?

Thanks
Yuanxi


2014-07-22 2:36 GMT-04:00 Michael Wimmer <wimmer@lorentz.leidenuniv.nl>:
Dear Yuanxi,

the way that attaching the leads works in kwant requires that the scattering region contains the same lattice as the leads. However, you can still easily achieve what you want: You only have to add a thin slice of lead lattice to the scattering region, this will also allow you to define all the irregular hoppings from the lead lattice to the scattering region. Then you can use attach_lead to add the lead to the system.

Adding a thin slice of lead lattice to the scattering region only creates a negligible computational overhead, and gives the same physical result (as what is "scattering region" and what is "lead" is mostly a matter of definition).

Best,

Michael

Am 22 jul. 2014 um 07:35 schrieb Yuanxi Wang <yuanxi.wang@gmail.com>:

Dear all, 

  I'd like to know if it is possible to construct/attach leads with lattices different from the main scattering region, or even leads with custom geometry unrelated to the scattering region? 

For example if my scattering region is an amorphous cluster whose geometry have defined by hand, and I want to build leads using their own lattice to the left and right. Is that allowed in KWANT? 

  (Of course in that case one would need define bonds/hoppings between and within the leads, and also from the lead to the main scattering region... but how..)

Thanks
Yuanxi

--
Yuanxi Wang, 
Pennsylvania State University 
Department of Physics 
104 Davey Lab #117, 
University Park, PA 16802 



--
Yuanxi Wang, 
Pennsylvania State University 
Department of Physics 
104 Davey Lab #117, 
University Park, PA 16802