Author Topic: Work function of functionalized graphene  (Read 41 times)

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Offline GJK

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Work function of functionalized graphene
« on: June 7, 2019, 13:33 »
Hi,

Request the procedure for computing the work function of functionalized graphene nanoribbon..For silver we have but what are the parameters to be fixed if we are to compute workfunction of GNR.A detailed procedure could help us in this regard

Already we are calculating chemical potential during optimization process.Can we use that result as work function or not???

Offline Petr Khomyakov

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Re: Work function of functionalized graphene
« Reply #1 on: June 7, 2019, 15:34 »
I do not see much of a difference when computing work function
 of functionalized vs. pristine graphene sheet, see the following tutorial for work function calculations,  https://docs.quantumatk.com/tutorials/work_function_ag_100/work_function_ag_100.html.

Offline GJK

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Re: Work function of functionalized graphene
« Reply #2 on: June 10, 2019, 13:15 »
Hi,

I have read this tutorial.For graphene nanoribbon. We  are already defining the structure for GNR as described by QUANTUMATK.

In the tutorial for Ag work function there are parameters for vacuum padding ,thickness  etc.
How to fix ghost atoms in GNR?? Do we need to perform surface cleave as said for Silver in your tutorial???

We are already calculating chemical potentail for our functionalized system.Can we take that as work function?? If not then how to fix the ghost atom and is surface cleave parameters necessary for GNR???

Offline Petr Khomyakov

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Re: Work function of functionalized graphene
« Reply #3 on: June 11, 2019, 09:47 »
If you already have a graphene sheet, you do not need to cleave it from the graphite crystal. In fact, you do not need to do it in any way, because a single graphene monolayer can be built by just increasing the out-of-plane lattice parameter of graphite to add a sufficiently-thick vacuum padding in-between the graphite monolayers.

Setting ghost atoms is more tricky. If you use plane-wave DFT calculator of QuantumATK, you actually do not need to use any ghost atoms. Otherwise, for LCAO-DFT it involves some experimenting. You  may first start doing these calculations without ghost atoms.