Bandstructure of Gated Graphene

[jack]

Dear sir,

I would like to calculate  the bandstructures of pristine graphene that lie on the gated substrate.Can do this calculation with QuantumWise?
Really, my purpose to get bandstructure is seeing the effect of gate voltage on Fermi energy (Ef) of graphene.

[kstokbro]

Yes, this is possible.
Put a gate below the graphene using miscellaneous panel in the builder.

When setting up the calculation, use the multigrid solver. For inspiration see:

http://www.quantumwise.com/documents/tutorials/latest/BenzeneSET/index.html/chap.SET.html

[jack]

Thank you!
In this example unit cell is cubic, but how can I define a gate for hexagonal unit cell of graphene?
Is it true that gate must be rhombus?
 

[kstokbro]

you can just let the gate stick out of the unit cell, the part of the gate not inside the unit cell is ignored.

[jack]

I don't understand,when the gate voltage is zero I expect  the fermi level will be zero, but in log file Ef=-1.081795 eV    .
And graphene without gate has Fermi Level  = -1.344273 eV. What's wrong?
I attach NetCDF file here.     

[kstokbro]

The workfunction of graphene is ~4 eV so the fermi level of graphene is 4 eV below vacuum level. Thus, compared to a zero gate, the sign of the fermi level is correct. In fact it could be more negative, however, this depends on the position of the gate.

[Anders Blom]

Don't confuse the Fermi level reported in the output with the Fermi level of a band structure plot. The logfile Fermi energy is given relative to vacuum, whereas in the band structure plot the energy scale is shifted such that the Fermi level appears at E=0.

[jack]

Thank you so much Mr. Blom and Mr. kstokbro.
My mistakes was in the number of K-sampling.