study of asymmetric electrode materials

[sweta]

Hello everyone,

I want to study the asymmetric electrodes in two probe system. The problem is that when we change right electrode material by editing script in editor and send to builder, it will convert into bulk rather device mode. How i can convert into proper device mode to study the junction system???

Thanks in advance!

[Anders Blom]

Probably you are making a mistake in the script, so the Python code for generating the DeviceConfiguration fails. I would recommend building the central cell in the Builder and using the usual way to convert it to a device, instead of attempting the manual edit.

[sweta]

Thanks for your quick response Dr. Blom.

I have made central device region. But when i convert it into device by selecting device from bulk and choosing left and right electrode length, it will change the shapes of electrode materials as that are in case of symmetric electrode materials.

[Anders Blom]

Can't assist without knowing more. Device from Bulk can handle this, at least in 12.2 and 12.8.

[sweta]

Hello,

In an article J. Phys. D: Appl. Phys. 46 (2013) 055309 they connect SWCNC directly with electrodes without taking central scattering region and therefore calculate bonding energy easily.

In ATK we take central region, so is this possible to calculate bonding energy? How to calculate this using ATK?

[Anders Blom]

As far as I can cell the bonding energy is computed for just the left electrode with the nanocone attached, calculated as a slab geometry. This is quite reasonable, I don't think it would be beneficial to compute the bonding energy in a device geometry.

You can do the same calculation in ATK (the authors appear to have used VASP for this), however one should note that to get a really accurate result you need to account for the basis set superposition error (BSSE). This is somewhat complicated, but we are working on an easier approach for ATK 13.8.

[sweta]

Thanks Dr. Blom.

How we can insert a molecule between two graphene nanoribbon electrodes to make molecular device geometry using ATK 12.8?

[kstokbro]

try the tutorials:
http://www.quantumwise.com/publications/tutorials/builder/172-building-a-molecular-junction-au-dtb-au
http://www.quantumwise.com/documents/manuals/latest/VNLTutorial/index.html/chap.gnr.html

These tutorials show the techniques you will need