Messages

61

General Questions and Answers / Re: basic principle of two probe system

« on: April 2, 2012, 14:53 »

Please see the attached image and tell me is the both images will give same results??
In first image I have chosen alignment layer 2,2 and second image 1,2. I got confused because some article prefer first image and others use second image.
I had taken 2,2. why they are taking different alignment layer for symmetric gold electrode on both sides?

Thanx in advance!

62

General Questions and Answers / Re: basic principle of two probe system

« on: March 30, 2012, 19:19 »

Thank you for your great response!!

Sir,
I want to study two probe system with different electrodes. I have done my study with gold electrode by taking position of anchoring group in fcc lattice (i.e. by setting alignment layer = 2) and all other parameters are taken as default parameters in custom builder molecular junction.

I want to do the same study with platinum electrode by taking same parameters as above but my problem is that when I drop platinum electrode to molecular junction, it increases the total number of atoms above 100 so its difficult to optimize the system.

Kindly help me how can I do the same study with platinum electrode (by taking all other parameters as that of gold electrodes) so that I can test effect of electrodes on our geometry.

63

General Questions and Answers / basic principle of two probe system

« on: March 29, 2012, 12:22 »

Hello,

I just want to know about the basic principle description of theoritical formalism (DFT-NEGF ) that ATK is using to calculate IV charecteristics of two probe system.

Thanx in advance!

64

General Questions and Answers / Re: 2 probe geometry problem

« on: March 2, 2012, 11:50 »

Thanx for your help sir.

What is the role of allignment layer 0-0,1-1, 2-2 of electrodes in two probe system. Is it related to top & hollow site of AU electrode.
How to measure distance between AU and anchoring group (say Sulphur) in above 3 allignment layer cases

65

General Questions and Answers / 2 probe geometry problem

« on: March 1, 2012, 08:43 »

Dear everyone,

There have been lots of work been done using dithiocarboxylate (-CS2) anchoring group in 2-probe system using ATK. Some of the articles I have mentioned here for your reference:

1. Torsion angle dependence of the rectifying performance in molecular device with asymmetrical anchoring group; Physics Letter A 374 (2010) 4876-4879

2. Negative differential resistance and rectifying behavior in atomic molecular device with different anchoring groups; Physica E 43 (2010) 524-528

I want to work with (-CS2) anchoring group and my problem is that when I make geometry by connecting (-CS2) group and then drop to molecular junction (custum builder) and then optimize the geometry. After optimization get changed.

 Please anyone help me how to make simple carbon dimmer geometry using dithiocarboxylate group properly so that both sulphur atom of CS2 will remain connected to AU electrode properly after optimization  

66

General Questions and Answers / how to make pantacene geometry

« on: February 27, 2012, 07:33 »

Hi everyone,

Can anyone please tell me how to make pentacene geometry in ATK builder??

Thanks in Advance!

67

General Questions and Answers / Re: how to optimize two probe system with functional groups

« on: February 21, 2012, 10:37 »

Hello Dr. Blom,

Please find the attached script and tell me why it is not running...

68

General Questions and Answers / Re: how to optimize two probe system with functional groups

« on: February 13, 2012, 17:05 »

Hi,

It is showing run time error.
The script i am using may or may not be the right script for optimization of two probe system. Since I dont know the right procedure for the same.
Can you please send me the right procedure or the whole script for two probe system optimization by taking dithiol sandwitched  between two gold electrodes??

69

General Questions and Answers / Re: how to optimize two probe system with functional groups

« on: February 9, 2012, 13:08 »

Its not working.

Can anyone send me the full script of optimizing the two probe system by taking dithiol molecule sandwitched between two gold electrodes.

Please help!

70

General Questions and Answers / Re: how to optimize two probe system with functional groups

« on: February 8, 2012, 06:45 »

I am using ATK-DFT(Device) calculator.
Please find the attached script

71

General Questions and Answers / how to optimize two probe system with functional groups

« on: February 7, 2012, 10:39 »

Hi,

I want to work on functionalized 2 probe molecular system. But when I optimize  functionalized dithiol sandwitched between two gold electrodes (having total 67 atoms using two electrode layers) in device configuration  (the procedure you given in the optimizing two probe mini tutorial). This program show run time error.
Why it shows this problem either it is parameters problem or 32-bit system problem???
I have taken mesh cutoff=150Rydberg,k-points=3,3,50, iteration steps=200, stress=.001, also tick no self iteration.

Please help me how to optimize functionalized two probe system??? and what parameters I should use so it will converge and optimize easily

72

General Questions and Answers / Re: how to choose AU-S bond length in molecular device

« on: January 27, 2012, 11:34 »

Thanx you so much sir.

Two more things:
1. how we can measure conductance in terms of G0 and then sulphur charge for two probe system
2. how we can make OPE geometry by creating bond between two carbon atoms in ATK-VNL.

73

General Questions and Answers / how to choose AU-S bond length in molecular device

« on: January 27, 2012, 08:21 »

Hello all,

In tutorial
http://www.quantumwise.com/publications/tutorials/mini-tutorials/76-simple-way-to-build-a-molecular-device-structure

you select adsorption height=1.71 Å which will give a distance Au-S=2.39 Å.
what is the relation between these two values??
what values of adsorption height I should choose that will give Au-S bond length= 2.33, 2.76, 3.06, 3.67, 4.29
Kindly help!

74

General Questions and Answers / Re: conductance of molecular devices

« on: January 21, 2012, 12:09 »

Sir my system clock is accurately set and automatically updated against time server. But after installation it showing the same error message.
I have also tried this installation for other system but showing the same error.
Please find the screenshot of the updated time and error message.
Please help!

75

General Questions and Answers / Re: conductance of molecular devices

« on: January 19, 2012, 10:43 »

Hi ,

As per your suggestion I tried to install a trial license version of the ATK 11.8.2 software in a 64 bit computer. But its showing the following error

 Licennse error: (Internal: 262 content: 1332665122 feature: VNL)
(Err:18) system clock has been set back

 I have attached the screenshot of the error being thrown. 

 Please let me know that is this trail version license key is compatible with 64 bit computer??

Please reply at the earliest as our work is dependent on your valuable suggestions. Hoping for a prompt reply.