Dear Zbigniew,

Thank you for sharing your work but this forum is meant for kwant advantages in solving physical problems.
Did you try this with kwant ? 
The answer to your question seems straightforward with kwant: lat.neightbors(n) gives you the nth nearest neighbour. You can extract the number of sites on a ring easily.


On Sun, May 3, 2020 at 4:36 PM Zbigniew Koziol <> wrote:

What is the number of neighbors on graphene lattice?

That question bothered me for 2-3 years. Finally, I found a way to solve the problem.

Did I find a something was already known? I guess not.

The issue may probably interest many of you on this list.

Please let me know what you think about my "solution"? I am myself very curious.

I am, BTW, interested in contacts (talking, solving problems, doing the work together, publishing together) with people who are on subjects close to graphene. Do not hesitate to contact me.

Number of equidistant neighbors on honeycomb lattice:


Zbigniew Kozioł, PhD,
National Center for Nuclear Research,
Materials Research Laboratory,
ul. Andrzeja Sołtana 7,
05-400 Otwock-Świerk, Poland
mobile: +48 507 330 216

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