Graphene growth on a copper surface - which potential and what starting configuration?

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1

Dear All!

I am currently thinking about how to grow graphene on copper foil the “MD way”.

I found a recent article “An analytical bond-order potential for carbon (pages 1719–1735) X. W. Zhou, D. K. Ward and M. E. Foster” using BOP and I think REBO is also available for copper-C system.

Has anyone attempted (and succeeded) in growing graphene by simply adding a layer of carbon on a sheet of copper and keep the system at elevated temperature? I am concerned because of the limited time available during MD.

Unfortunately I am relatively new to LAMMPS and I apologize if this is a too basic question!

Yours,

Chris

2

I suggest finding a paper in the literature

where it’s been done (if such a paper exists)

and start from there.

Steve

3

What you need is a potential that describes Cu and C at the same time, without using hybrid to mix and match different potentials together.

I suggest you look at ReaxFF and COMB3 potentials, which have potential parameters for Cu-C working together.

Ray

4

Dear Steve, Dear Ray!

Thank you for your fast reply! When I searched the literature I came across an interesting paper describing Graphene growth on Copper for an BOB (X.W. Zhou, J. Comp. Chem. 2015, 36). Because I use a school computer I can only use COMB3 potential (which is also shown in that paper) so I am planning to replicate their process but I am a bit stuck in equilibrating my sample properly.

What I am attempting to do is create an Cu slab and then deposit a layer of carbon (actually distorted graphene) and try to see if they assemble into graphene at elevated temperature.

I am wondering how to perform thermal “equilibration” in an efficient way in a non-periodic system? Maybe someone can help me out. There is apparently the minimize command or I can use an NPT sample (or probably rescale the temperatures?), but I am not sure how they differ.

Further the paper cited above manages to “inject” atoms towards the graphene surface, can someone point me towards that functionality in LAMMPS?

simulates the growth of graphene from carbon deposited on top of a copper slab

through simulated thermal annealing using comb 3 potential

units metal

atom_style charge

dimension 3

boundary p p s

copper slab

lattice fcc 3.65

region box block -10 10 -20 20 -3 3

region slab block -10 10 -20 20 -3 0

create_box 2 box

create_atoms 1 region slab

#graphene island

variable alat equal 2.5

lattice custom ${alat} &

a1 1 0 0 &

a2 0 1.732050807569 0 &

a3 0 0 3.35 &

basis 0 0 0 &

basis 0.5 0.166666666667 0 &

basis 0.5 0.5 0 &

basis 0.0 0.666666666667 0 &

region sheet prism -5 5 -5 5 1 2 0 0 0

create_atoms 2 region sheet

group graphene region sheet

displace_atoms graphene move 0.0 0.0 -0.7 units lattice

displace_atoms graphene random 0.1 0.1 0.0 1547

atom_modify sort 0 0

atoms

mass 1 63.54

mass 2 12.011

thermo 50

thermo_style custom step temp pe etotal press vol

thermo_modify lost warn norm yes

velocity all create 100.0 53244 dist gaussian mom no rot no

dump 1 all xyz 100 graphene.xyz

dump_modify 1 element Cu, C

run 20000

Thank you for your time and help!

Yours,
Chris

5

Dear All!

Sorry but I sent my previous message from the wrong email account so it bounced and you can disregard it!

I want to restate my question. I am attempting to “grow” graphene. Initially I will deposit graphene in proximity of a copper surface, distort it and check if it will “re-arrange” at typical growth temperatures. Later I want to “add” carbon atoms to the grid to see if they properly attach.

a) For thermal annealing using non-periodic boundary conditions: what is a “good” ensemble/method to use at non-zero temperatures?

b) How can I “inject” atoms to my box at certain times (as done in X. W. Zhou J. of comp. Chem. 2015, 36)

Below is my current code and attempt to run a temperature ramp, if someone has a comment on it I would be grateful (I am generally just wondering if that is a good/acceptable approach or not)

Thank you all for your support and time!

Yours,

Chris

simulates the growth of graphene from carbon deposited on top of a coppers slab

through simulated thermal annealing using comb 3 potential

units metal

atom_style charge

dimension 3

boundary p p f

copper slab

lattice fcc 3.615

region box block -10 10 -20 20 -3 3

region slab block -10 10 -20 20 -3 0

create_box 2 box

create_atoms 1 region slab

#graphene island

variable alat equal 2.46

lattice custom ${alat} &

a1 1 0 0 &

a2 0 1.732050807569 0 &

a3 0 0 3.35 &

basis 0 0 0 &

basis 0.5 0.166666666667 0 &

basis 0.5 0.5 0 &

basis 0.0 0.666666666667 0 &

region sheet prism -5 5 -5 5 1 2 0 0 0

create_atoms 2 region sheet

group graphene region sheet

displace_atoms graphene move 0.0 0.0 -0.7 units lattice

displace_atoms graphene random 0.1 0.1 0.1 1547

atom_modify sort 0 0

atoms

mass 1 63.54

mass 2 12.011

pair_style comb3 polar_off

pair_coeff * * ffield.comb3 Cu C

thermo 50

thermo_style custom step temp pe etotal press vol

thermo_modify lost warn norm yes

velocity all create 100.0 53244

fix 1 all npt temp 300.0 300.0 0.02 x 0.0 0.0 1.0 y 0.0 0.0 1.0

run 10000

unfix 1

fix 2 all npt temp 300.0 1400.0 0.02 x 0.0 0.0 1.0 y 0.0 0.0 1.0

run 10000

unfix 2

fix 3 all npt temp 1400.0 300.0 0.02 x 0.0 0.0 1.0 y 0.0 0.0 1.0

run 10000

dump 1 all xyz 2000 graphene.xyz

dump_modify 1 element Cu, C

6

Dear All!

Sorry but I sent my previous message from the wrong email account so it
bounced and you can disregard it!

I want to restate my question. I am attempting to “grow” graphene. Initially
I will deposit graphene in proximity of a copper surface, distort it and
check if it will “re-arrange” at typical growth temperatures. Later I want
to “add” carbon atoms to the grid to see if they properly attach.

a) For thermal annealing using non-periodic boundary conditions: what
is a “good” ensemble/method to use at non-zero temperatures?

you won't have a standard statistical mechanical ensemble under those
conditions.
for annealing, you are generally best off using a dissipative
thermostat (any of the langevin variants or temp/csvr).

b) How can I “inject” atoms to my box at certain times (as done in X.
W. Zhou J. of comp. Chem. 2015, 36)

have you looked at fix deposit?

Below is my current code and attempt to run a temperature ramp, if someone
has a comment on it I would be grateful (I am generally just wondering if
that is a good/acceptable approach or not)

this is really beyond the scope of this mailing list. you are asking
how to do you research and that is something that you need to discuss
with your adviser. as steve already mentioned, you can use previous
publications as guidelines. ...and in order to determine, if something
is working well, you will have to devise tests to verify that your
choices are good. this is just standard practice for everybody and
cannot be replaced by asking a bunch of random people on a mailing
list.

axel.