Build silicene nanoribbons

[Anders Blom]

Yes you might need to swap axes to align the transport direction, but that will be needed anyway because the C axis (the transport axis in QuantumATK) is perpendicular to the sheet in the original system.

After the supercell operation as indicated above, it's very simple to make armchair and zigzag by noting that the new A direction is along the zigzag direction, and B along armchair, as you can see if you make some repeats (picture below).

[Mubashir hamid]

Do I need to add vacuum in one of the directions apart from transport direction (i.e. either X or Y ) to form a nanoribbon after following the above mentioned steps

[Anders Blom]

That is the definition of a nanoribbon, yes... And hydrogen passivation of the edges

[Mubashir hamid]

Do I passivate the edges by using custom passivator with sp2 ?

[Anders Blom]

It's a bit trickier with the buckled sheet, since the automatic passivation tool does not recognize it as sp2 when it's not flat, but you are absolutely right that the Custom Passivator (should really be called Advanced Passivator...) will manage it when you explicitly select sp2!

[Mubashir hamid]

Thanks for your help on Zigzag Silicene Nanoribbons. I wanted to know how can we set up the antiferromagnetic configuration of Zigzag Silicene Nanoribbons which would be later on used for band structure calculations

[Anders Blom]

Some tips here https://docs.quantumatk.com/tutorials/spin_bloch_gnr/spin_bloch_gnr.html

[Mubashir hamid]

thanks for the link. However in this tutorial it is written that "Since the up and down Bloch states are localized on opposite edges, there must be a difference in the total spin up and down electron density. The Mulliken populations is the easiest way to get a first view of this. Under the column “Total”,the two spin-channels are shown on separate lines, and we find that the two edge carbon atoms(numbers 0 and 1) have a surplus population of 0.25 of either spin-up or spin-down". What if one does not obtain any difference that is to say that the spin channels on the separate lines have same values?

[Anders Blom]

Then there is no net spin polarization across the ribbon