[lammps-users] single sheet of graphite

Dear user,

Actually i want to make a single sheet of graphite in 2D with lattice command. A sample picture is attached with this mail. My problem is that there should be no center atom as shown for case of two hexagon.

Thanking you.
apurba

Mr. APURBA MANDAL

M.Tech(Mechanical Engineer)

Ukil Bagan(Feeder Road)

Shaymnagar,North 24 Parganas

West Bengal

graphite_sheet.PNG

Probably the lattice command creates a unit cell and populates lattice points with replicas of the unit cell. This will create two layers of graphene. What you can probably do is write out the data, filter out one of the layers by a one line gawk script (gawk '{if ($3 > Zvalue) print $1, $2, $3) ad read in the data file in the subsequent simulation.

Else create the graphene layer co-ordinates yourself and read_data.

Best Regards,

Manoj

2009/4/16 apurba mandal <apurba005@…555…>

If you can't define your geometry as a repeated unit cell with basis
atoms, then you'll have to build the system yourself and input it
as a data file.

Steve

Dear Apurba,
Create a unit cell for a single graphene and then replicate it using replicate command. Here is some info if you want.
A graphene unit cell (rectangular in nature) will have 4 atoms at the positions

  1. 0 0 0
  2. a 0 0
  3. 3a/2 sqrt(3)/2 0
  4. 5a/2 sqrt(3)/2 0

Also, it periodic cell will be 3a along X direction and srqt(3)a along Y direction. Create such a sample file and then use replicate command in lammps to get the structure of any size that you want. This will only give you a set of coordiates so you can use it with only coordinates based potentials such as AIREBO, Tersoff where you dont have to specify bonded information in the datafile.

Regards,
Vikas