Dear Amrita,

Yes, you can add the two builders as follows:

but in the new version of kwant, the operator += for builders is deprecated. So, you better use:

and then you add your missing hopping, before you attach the lead:

I don't know why you separate your lead into two parts and then build it again, but you can get it directly in one shot.

I hope this helps.

On Fri, Feb 23, 2018 at 10:04 PM, amrita chapagain <> wrote:
Thank  you Adel for prompt reply. I have another query here. Can I add these two system together incorporating missing hopping elements? 

Abbout Adel