Nanosheet and nanoribbon builder in VNL

[Heinz]

Hello

I tried nanoribbon and nanosheet builder in VNL but confused a lot. When I generate N=10 zigzag GNR, all edges are passivated by hydrogen. When I generate n=3 and m=3 carbon nanosheet, the same structure with N=10 ZGNR is generated but hydrogen atoms are replaced by carbon instead. So, what does the nanosheet builder actually do? And is n=3 and m=3 nanosheet realistic and is it the one called unpassivated GNR? Thanks for your comments. Is the unpassivated GNR=nanosheet in VNL?

[Umberto Martinez]

no, the two configurations are very different.
nanosheet is 2D, periodic in the y and z directions.
nanoribbon is 1D, periodic in the z direction only.

try to repeat the two structures along the Y/B direction (Bulk Tools->Repeat) an you will see the difference.

[Heinz]

Thanks a lot. So what's the structure attached is called? It is periodic in C direction (1-D) structure so not a nanosheet.

[Umberto Martinez]

graphene sheet. It definitely looks periodic both in C AND in B directions.
Once again, try to repeat it in the B direction.

we have many tutorials on graphene nanoribbons that you can check to have a better understanding of the system:
http://quantumwise.com/publications/tutorials

[Heinz]

Thanks again, I now see when repeated in B direction. From implementation viewpoint, can the previously attached structure be produced as unpassivated GNR (when repeated in C direction and not repeated in B direction)?

[Anders Blom]

The repetition in B is implicit, it's part of the computational model (boundary conditions), so no. But you can just build a nanoribbon and delete the H atoms (or just don't include them in the first place, there is a checkbox for it).

[Heinz]

Thanks.