C = sisl.Atom(6)

"""
Explanation: Create the input required for a full TranSiesta calculation. Here you should create your first system with these settings:

A pristine bulk Carbon-chain system.
The Carbon-chain should have a bond-length of $1.5\,\mathrm{Ang}$ and lots of vacuum in the transverse directions (to make it a chain)
You should decide in which direction the semi-infinite directions are.

Please use the script tselecs.sh to create the relevant input for TranSiesta.
Below you will find a skeleton code that only requires editing from your side.
End of explanation
"""


elec = sisl.Geometry(<fill-in coordinates>,
                     atoms=C,
                     sc=<unit-cell size>)
elec.write('ELEC.fdf')

"""
Explanation: Create the electrode.
  Supply the coordinates and the supercell.
  Note that you have to decide the semi-infinite
  direction by ensuring the electrode to 
  be periodic in the semi-infinite direction. You should also ensure nearest neighbour electrode couplings only!
End of explanation
"""


device = elec.tile(3, axis=<semi-infinite direction>)
device.write('DEVICE.fdf')

"""
Explanation: Create the device.
  The basic unit-cell for a fully periodic device
  system is 3-times the electrode size.
HINT: If you are not fully sure why this is, please see TS 1.
End of explanation
"""


