z-shape cnt junction

[Maneesh]

Dear sir,

Is it possible to build up z-shape cnt junction devices as given in the graphene junction devices tutorials .
if buildup z shape cnt junction another softwere the z-shape cnt twist when in bulk mode convert. how to remove
this problem . please suggest to me


thanks


                                        maneesh

[Anders Blom]

Sorry, I didn't quite understand the problem. Can you perhaps show it in pictures and ideally with input Python script too.

[ams_nanolab]

Hi Maneesh, I guess the problem u are facing is because of an issue with the graphics accelerator... if u are using windows make sure the graphics drivers are all properly installed and hardware acceleration is enabled... cheers

[Maneesh]

Dear sir

I have constructed z-shape carbon nano tubes using other software which I have converted in to xyz format and then use atkvnl  droped the file in builder and I have obtained the z-cnt .But when I tried to make a device and tried to connect it to the electrodes it does not work and the z-cnt didn't get connected to the electrodes.
for your kind reference I am enclosing the structure.
it would we mice if you make a device of it. i attach the image file

thanks


                              maneesh

[Anders Blom]

There is not much we can do with just the picture of the structure, but the general rule is that you need to have a bit of perfect nanotube at the edges which can be interpreted as electrodes. Specifically, you need to have at least one repeated pattern. It looks like your system has been run through an MD simulation or similar, which has make the tube a bit imperfect at the edges. What you can do is to add 2 repetitions of the corresponding perfect nanotube (same chirality) by hand to the two edges in the VNL Builder; use the Move tool to move it into reasonable place, and also to rotate around Z if needed. Then build the device based on that (perhaps reduce the central region a little bit if you want), and finally run a Quick Optimization or MD simulation on the device in ATK.

[Maneesh]

Dear sir ,

 I am attaching a z-shape cnt to be placed for device calculation. when I place the z-shaped structure from bulk to device   the structure's ends breaks in the electrode area. I have tried it several times but failed to put it correctly. it would we nice   of you,if you please convert this structure in a device and send it to me, so that I may run the calculations. For your kind reference I am attaching the python's and word file.

  thank you


                                  maneesh   
 

[Anders Blom]

First, a tip. To post pictures in the Forum, just post the PNG file - there is no need to wrap it in a Word document, it just makes it harder for people to view it (not everyone is so comfortable downloading an unknown doc file).

Second, you're almost there for this exciting system, but there is a small challenge left. In order for the electrode to be properly formed, you must have to the left and right a piece of the nanotube which is parallel to Z, and include enough of it to make a proper periodicity. I would suggest a rather simple procedure:

* Make a clean segment of a nanotube with the relevant chirality in the Builder - repeat it in C enough times that it is longer than 8 Å.
* Attach it to the left and right edges of your current system as best you can by following a similar procedure with the Move tool as described in the tutorial on capping a nanotube (http://quantumwise.com/publications/tutorials/builder/185-capping-a-carbon-nanotube)
* Create the device enough of the nanotube as electrode to form an electrode that is about 8 Å long - afterwards you may decrease the part in the central region a little bit since you already have a lot of nanotube in the current system
* Run a quick optimization (found under Coordinate tools)

Before this, you may possible want to remove a little bit of your current system not to make it too long in Z (i.e. replace a bit of the current edges with the perfect tubes), but that's up to you.

Good luck - I look forward to seeing the results of the calculation!