[QE-users] VACUUM POTENTIAL NOT ZERO CALULATION

[Barsha Pal]

Hello everyone,
Firstly I am grateful to the Quantum Espresso Team for building this free
software and maintaining this forum, all without any costs. You have truly
taken a step forward for growing education without any possible fees.

*Coming to my questio**n*, I am trying to calculate the vacuum potential of
a hexagonal unit cell of graphene of  two atoms. I proceed in the following
way:

*What I did:*
1) scf with pw.x
2) pp.in with pp.x
3) using a code to find the planar average electrostatic potential in the z
(vacuum) direction. As I could not figure out how to use the average.x tool.
4) identify the vacuum potential, which in my case is not zero (should be
zero as written in literature https://doi.org/10.1016/j.ijhydene.2022.09.249
).

all the files are attached.

*My question is that:*
1) is my method correct ?
2) if yes then why is the vacuum potential non zero? What can I do to make
it zero ?
3) I am trying to find the vacuum potential so that I can calculate work
function and vbm cbm values with respect to vacuum potential for
photocatalytic application.

Kindly help me. I have been stuck at this for a long time.


google drive link
<https://drive.google.com/drive/folders/1knK2PNlKFH26ri84sLJGKM2LVRN789BC?usp=sharing>
.
I have attached all the files in the google drive link. If you can't read
it I'll send in whichever manner needed.


Ashley Cooper
Phd
Assam University Silchar
Assam, India
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