[DFTB-Plus-User] R: Transport calculation with gate field.

[Alessandro Pecchia]

Dear Anshu,

in most cases a simple transverse electric field is not quite the same as an electrostatic gate. It is true that a gate pad generates an 'almost' uniform electric field in its vicinity, but what matters more for electronic devices is the potential shift induced with respect to the other contacts. This is what actually makes a FET working, e.g. opening and closing the transport channel. 
   
So, in practice, if you are interested on S/D transport like in a FET configuration then you should simulate the presence of a gate. 

In dftb+ you can set a planar gate (see manual) in the x-z plane (field along the y plane). Pay also some attention on how you set the boundary conditions at the contacts. Compare the default with BoundaryRegion options.

Regards,

Alessandro 


-----Messaggio originale-----
Da: DFTB-Plus-User [mailto:dftb-plus-user-bounces at mailman.zfn.uni-bremen.de] Per conto di Anshu Gaur
Inviato: lunedì 20 giugno 2022 14:12
A: dftb-plus-user at mailman.zfn.uni-bremen.de
Oggetto: [DFTB-Plus-User] Transport calculation with gate field.

Dear all,

I am doing some transport calculations with applied (planar) gate potential. Separately I have done some calculations with applied electric field (external, saw-tooth potential) to see the changes in the band structure of the scattering region.

I would like to know, if transverse electric field related changes in band structure of scattering region would reflect in transport calculations with applied gate potential?


Thanks and regards,

Anshu Gaur

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