Messages

31

Scripts, Tutorials and Applications / Re: I-V curve tutorial problem

« on: January 9, 2012, 06:07 »

I am getting this Error after the above step . ...Is it not possible with EHT ?

+------------------------------------------------------------------------------+
| NanoLanguageScript execution started                                         |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
|                                                                              |
| Atomistix ToolKit 11.8.0 [Build 308f600]                                     |
|                                                                              |
+------------------------------------------------------------------------------+
Traceback (most recent call last):
  File "/tmp/1360052463028704.py", line 18, in <module>
    zero_bias_potential = EffectivePotential(configuration)
  File "./zipdir/NL/Analysis/EffectivePotential.py", line 37, in __init__
  File "./zipdir/NL/Analysis/Analysis.py", line 74, in __init__
  File "./zipdir/NL/Analysis/Analysis.py", line 66, in _supportConfigurationWithCalculator
  File "./zipdir/NL/Analysis/Analysis.py", line 52, in _supportCalculator
NL.ComputerScienceUtilities.Exceptions.NLTypeError: The DeviceHuckelCalculator does not support calculation of EffectivePotential.
+------------------------------------------------------------------------------+
| NanoLanguageScript execution finished                                        |
+------------------------------------------------------------------------------+

32

General Questions and Answers / Re: How to get electrode coordinates for two probe system

« on: January 6, 2012, 08:17 »

This will be so much easier to do in ATK 12.2. We are currently make a completely new Builder, where this system is one of the test cases, which we are making sure is easy to build.

So, since that is coming out relatively soon, but not tomorrow, I decided to make the simplest solution possible (for me) which anyway works in 11.8.

The result is the quick-and-dirty Custom Builder attached to this post. How way to use it:

• First save this script on your computer.
• Then, drop it (the file) onto the "Custom" icon in VNL.
• You can drop any cubic metal like Cu or Au or Pd etc onto the "New electrode" dropzone (default is gold). It must be cubic because we need to cleave it. A simple extension would be to allow also ready electrodes; then one could also build pure nanotube or graphene junctions
• Now open another Custom Builder and select Nanotube from the menu. Choose the indices you want, and remember to repeat it so it's long enough.
• Then drag and drop the nanotube, using the script icon in the lower right-hand corner, onto the dropzone "Drop center bulk here".
• Now you can make some adjustments in terms of repetitions (in X/Y) distances etc so that you get something reasonable.
• Note that you can actually take any bulk system and put in the middle. So also some piece of graphene would work fine.

One thing you may want to "post-process" is to rotate the tube, or fine-tune it's position. This can be done in the Builder, by selecting all carbon atoms (right-click background, Select>Select by>Elements), and then use Transform>Rotate or Translate.



Let me know if you find any mistakes or problems with using it.

I want to use the above script to build a schottky diode by replacing the left electrode with Aluminum(110) and right electrode with Palladium/Gold or any other ohmic contact and drop a CNT(8,0) in the centre bulk ..Is my procedure correct .

33

General Questions and Answers / Re: Error ---:Path not found

« on: December 31, 2011, 16:40 »

Thanks i will do again

34

General Questions and Answers / Re: Error ---:Path not found

« on: December 31, 2011, 15:48 »

In the script which you drop on the Job Manager, make sure to specify the FULL path (not just the filename) of the NC file.

But sir in the following script in the tutorial , its the scf file name only there is no path

01.# Define input and output NetCDF files here
02.scf_filename = "lih2li_iv_scf.nc"
03.analysis_filename = "lih2li_iv_analysis.nc"

i have put both generated .nc file and the downloaded script in the same folder ..

35

General Questions and Answers / Error ---:Path not found

« on: December 31, 2011, 10:23 »

+------------------------------------------------------------------------------+
| NanoLanguageScript execution started                                         |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
|                                                                              |
| Atomistix ToolKit 11.8.0 [Build 308f600]                                     |
|                                                                              |
+------------------------------------------------------------------------------+
Traceback (most recent call last):
  File "/tmp/4850306596851799.py", line 8, in <module>
    configurations = nlread(scf_filename, DeviceConfiguration)  
  File "./zipdir/NL/IO/NLSaveUtilities.py", line 219, in nlread
NL.ComputerScienceUtilities.Exceptions.NLValueError: The filename, IV_CURVE_and_voltagedrop.nc, was not found - please check correct path and name.
+------------------------------------------------------------------------------+
| NanoLanguageScript execution finished                                        |
+------------------------------------------------------------------------------+



I am getting the above error repeatedly even if i do it as shown in the tutorial.

http://quantumwise.com/publications/tutorials/mini-tutorials/98-i-v-curve-and-voltage-drop

36

General Questions and Answers / Re: Correction of Carbon-Aluminum Bond Length and Structure

« on: December 22, 2011, 05:32 »

The paper by Bai et al used the ATK-DFT calculator rather than EHT.  The atomic structure of CNT-Al can be optimized using the "Optimization" tool, as mentioned by you. The key issue is that it may be very difficult to reproduce the atomic structures (e.g.the bond lengths) in their paper, because the several important parameters in their calculation setup were not presented implicitly.  The feasible way is to just follow the idea and simulation procedure of their paper, rather than focusing on the details of simulation parameters (such as the bond lengths).

Thanks a Lot 

37

General Questions and Answers / Correction of Carbon-Aluminum Bond Length and Structure

« on: December 19, 2011, 06:49 »

I tried to create a structure shown in the paper below (Fig 1 and 2) in the ATK builder by inserting Aluminum atom in the CNT(8,0)
How do i correct  the bonds of carbon -Aluminum and the Overall Structure Can the bond lengths can be corrected by running the "optimize " tool in the scripter and using EHT . Also do we Need extra packages or add-ons/tools to create that structure easily....
 
A Comprehensive Atomic Study of Carbon Nanotube Schottky Diode Using First Principles Approach
Ping Bai,   Kai Tak Lam,   Erping Li ,  Chang, K.K .

38

General Questions and Answers / Re: Armchair Nanoribbon to CNT

« on: December 15, 2011, 18:33 »

thanks a ton

39

General Questions and Answers / Re: How to Study metal-Semiconductor juntions in VNL

« on: December 15, 2011, 13:04 »

The removal of some atoms in VNL can be manipulated by the functionality of "Builder". (Select--->Delete)

The choice of the calculator may depend on your the accuracy required in your study. The DFT calculator is the much better one than Extended Huckel to produce more reliable results.

Sir...I did as You Said using ZAZ structure (using Default values )and opening it in builder deleting the other metal part ..but since i dont have a ATK-DFT license i used extended Huckel calculator(using Default values )

Please see the bandstructure generated due to the above process .Is it correct for a metal-semiconductor junction .

Thanks

40

General Questions and Answers / Re: How to Study metal-Semiconductor juntions in VNL

« on: December 15, 2011, 09:18 »

You can first build a two-probe system of metal-cnt-metal using the tool in VNL, and convert it into an equivalent bulk system.  This system will be an example of metal-CNT interface without the use of vacuum region. To build a interface structure with the use of vacuum region, it is achieved easily by removing either of the two metal electrode regions.

Very much Thanks for your suggestion ...How can i remove one of the metal electrode ?....Should i remove the atoms of the electrode by opening the structure in builder ?
And which calculator should i use for simulation..Extended huckel or DFT ?

41

General Questions and Answers / Armchair Nanoribbon to CNT

« on: December 14, 2011, 13:22 »

Hi ..In the Quantum wise Tutorial its Mentioned that ..Armchair Graphene nanoribbons shows Semiconductor property only and ziz-zag shows metallic...But I read Somewhere that semiconducting or metallic property of a Armchair nanoribbon depends on the Width of the ribbon....So that we can get a "metal" or a "semiconductor" by adjusting the width...Please help .

Another thing...Suppose we get a armchair nano-ribbon((sheet) as semiconductor by computing the band structure in VNL...Now suppose if we roll the sheet will we get a Ziz-zag carbon nano-tube with the same semiconducting property or it will be metallic and vice Versa .

So basically i want to Fully understand the relation between Graphene nano-ribbon(GNR) and Carbon Nano-tube and and how to roll and unroll them  ....and how their electronic properties affects .............


Sorry for the newbie questions but i really need to know this things ..

42

Installation and License Questions / Re: How to replace the Old license with new one

« on: December 14, 2011, 04:32 »

Thanks Sir..its working now 

43

Installation and License Questions / Re: How to replace the Old license with new one

« on: December 13, 2011, 09:56 »

Yeah i managed to copy it by logging into root But Its giving this Error Now.

(I removed the older license from the folder)


License Error: (Internal: 292 Feature: VNL)

(Err: 9) Feature not found

For further assistance consult the manual or contact QuantumWise.

44

Installation and License Questions / How to replace the Old license with new one

« on: December 13, 2011, 08:33 »

Hi...when i try to replace the old license with the new one(By copying) into the directory opt/Quantumwise in Redhat Linux i get the following error "Access denied " .

Please help

45

General Questions and Answers / How to Study metal-Semiconductor junctions in VNL

« on: December 13, 2011, 07:04 »

Please give me directions on  how to Study a Metal-Semiconductor (metal-nanotube) Interface for a Schottky diode in ATK..

Thanks