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How can I build a 3x3x1 rectangular supercell from the hexagonal unit cell of graphene by using VESTA?

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    $\begingroup$ Isn't this very similar to this post? mattermodeling.stackexchange.com/questions/11042/… Possibly, you want a specific looking shape, but the answer in that post provides a framework to figure out other matrices that can let you tune to the rectangular cell you want. $\endgroup$
    – CW Tan
    Commented Jun 22, 2023 at 11:46
  • $\begingroup$ Thank you, Mr.CW Tan, your addition in the previous post is very useful, but I could not make a 3x3x1 rectangular supercell $\endgroup$ Commented Jun 22, 2023 at 16:33
  • $\begingroup$ The simple answer is: you can't because the only thing that creating a supercell does, is to use translation to replicate the initial cell. So, if you start from a hexagonal symmetry, you will always end with a hexagonal supercell. BUT you can manually delete some atoms and "force" the structure to look like it is rectangular. $\endgroup$
    – Camps
    Commented Jul 2, 2023 at 14:03

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In VESTA you can either visualize multiple repetitions of a unit cell, or multiply your unit cell a number of times to really create a supercell. I'll explain both cases now.

Visualize repetitions of a unit cell:

  1. Go to Objects $\rightarrow$ Boundary
  2. Under ranges of fractional coordinates, chose the minimum and maximum limits along the three axes. For your example of a $3\times3\times1$ supercell you could chose something like: x(min)=0, x(max)=3, y(min)=0, y(max)=3, z(min)=0, z(max)=1
  3. click "Apply" to continue, or "OK" to exit the Boundary menu.

Create supercell:

  1. Go to Edit $\rightarrow$ Edit Data $\rightarrow$ Unit cell
  2. Click on "Transform"
  3. On the "Rotation matrix P" change the values to create the required supercell. For your example of a $3\times3\times1$ supercell you should change only the diagonals to be $3, 3,$ and $1$, with $0$ on all off-diagonals.
  4. Click "OK"
  5. If prompted about the transformation changing the unit cell volume, agree to continue.
  6. When asked how to convert the structure chose the option "Add new equivalent positions" (or similar).
  7. click "Apply" to continue, or "OK" to exit the Edit data menu.

All of the instructions here are given for the mac version of VESTA, but they should be very similar in other versions.

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  • $\begingroup$ Hi, thank you for adding. Actually, still I get a hexagonal supercell not a rectangular one. $\endgroup$ Commented Jun 22, 2023 at 10:49

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