Messages

1

General Questions and Answers / Re: Changing two probe system to 3 terminal device.

« on: December 19, 2013, 01:29 »

But if your structure is really like Au-DTB-Au, I don't think it's very physical to try to squeeze in a metallic "gate" the size of a benzene molecule or smaller. A more relevant option might be to add some charge to the molecule (that's basically what the gate does anyway).

Thank You for your reply.

I will now try the option of adding charge to molecule. but before doing this I have a question. Can we introduce charge in DeviceConfiguration(Two Probe system)? As in two probe system the extra charge in the device region would die out into the electrodes and the net charge would vanish out.

Could you tell me the reference to find procedure for adding charge in two probe system.
 
Regards and Thanks

2

General Questions and Answers / Changing two probe system to 3 terminal device.

« on: December 18, 2013, 10:54 »

Dear sir,

Can I change two probe molecular system (for example au_dtb_au_geom) to three terminal device by introducing "metallic Box" in the "central region" ? Is this the right way?

Regards

Ali Zahir

3

General Questions and Answers / Help Needed: Gated molecular Device

« on: December 17, 2013, 16:34 »

Hello Sir,

I am also trying to introduce gate electrode in ATK Simulator using DFT-NEGF method. while doing this I faced following problems.
 
1.  When I tried to introduce Gate "metallic region" in "Central region", then even with out applying any gate voltage, the transmission function and the molecular orbital shifts and get aligned with fermi level of the system.  
  
2.  I keep this distance between molecule and gate 4-6 A, but the applied gate has no effect on the transmission spectrum and molecular orbitals of the system (there is no shift in molecular orbitals). I am using 12.8.2 version of ATK.

3.  When I try to change the boundary condition in "Poisson solver" to "Neumann" for  A-direction and B-direction, I get completely different transmission spectrum (noisy one)  .

Can any body help me how to introduce gated voltage in ATK for DFT-NEGF calculation ?.
 
Thanks in advance

Ali