Atomic Coordinates for nanowires

structure determination,...

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Nedhal
Posts: 2
Joined: Thu Oct 24, 2019 1:20 pm

Atomic Coordinates for nanowires

Post by Nedhal » Fri Nov 06, 2020 2:40 pm

Do we extract nanowire from bulk, where
I built the structure for bulk silicon in VESTA software  in oriented along a surfaces ( 100), (110) and (111)( cuted ) without neglecting existence of vacuum along x and y directions. and I got  its atomic coordinates and I used it as nanowires in Abinit, Is that right  ?

ATOMS
NAME X Y Z
Si 0.250000 0.250000 0.000000
Si 0.250000 0.250000 1.000000
Si 0.250000 0.750000 0.000000
Si 0.250000 0.750000 1.000000
Si 0.250000 0.500000 0.500000

mverstra
Posts: 655
Joined: Wed Aug 19, 2009 12:01 pm

Re: Atomic Coordinates for nanowires

Post by mverstra » Fri Nov 06, 2020 3:28 pm

Hello Nedhal,

So, the general idea is ok. However you need to worry about the following things:
- abinit is a periodic plane wave code, so you need PBC with vacuum perpendicular to the wire and to find a periodic slice of the wire along the axis. You will need to ensure the atom positions and "c" lattice constant correspond, and there is no spill out or overlap of positions
- the coordinates you use here are reduced. To make supercells wires and tubes, you will need cartesian coordinates, because you will add layers and make the cell bigger perp to the wire. The xcart will stay invariant there
- Start with a supercell which is oriented with c along the direction you want (111...) This is basic geometry and solid state physics.
- Then you can draw the extent of the wire cross section, and decide how many layers you need along the axis (for a perfect wire, use the minimum which is typically 1, 2, or 3 atomic layers).
- one thing you might try is the virtual nano lab from atomistix / syoptics. I don't know if they still have a free download version (they did in 2016), but it's very ergonomic to make and chop structures. There may also be other free tools online to make nanotubes and wires. Have a search online. If anyone has suggestions please answer this thread

ciao

Matthieu
Matthieu Verstraete
University of Liege, Belgium

Nedhal
Posts: 2
Joined: Thu Oct 24, 2019 1:20 pm

Re: Atomic Coordinates for nanowires

Post by Nedhal » Fri Nov 06, 2020 3:40 pm

Dear ciao and Matthieu,




Many thanks for your answer, It is very kind of you

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