Messages

1

General Questions and Answers / Transmission and its relation on Current

« on: September 5, 2011, 12:30 »

Hi

Is current anyay related to the values of transmission. like if it is directly proportional to value of transmission??

i measured the current carried by a small AGNR for different potential biases and plotted its transmission spectrum

then i removed an atom from the AGNR and then plotted its transmission spectrum

though the value of transmission had decreased in the second case, the current conducted at certain potential biases is like 8 times the current carried by the defectless structure.

can this thing be right??

i have attached the images of AGNR's i used

regards
deepak

2

General Questions and Answers / Re: A clarification about IV characteristics

« on: August 19, 2011, 20:07 »

oh

i introduced a double defect and a stone walles defect as as well but in all cases the current in defective ones were higher than that in defect less ones (ratio varies like 1.5 to 2 for the three of them)

3

General Questions and Answers / A clarification about IV characteristics

« on: August 19, 2011, 14:18 »

Hi

i had formed a small AGNR with m=0, n=5 and z axis repetition 4 and calculated its current at 1.5 V bias and removed an atom from the center of the structure and calculated its current at 1.5V. I was hoping that current in the defectless structure would be high. But it turned out that current in structure in which an atom was missing was high (all other parameters were same and both structures were optimized using Brenner potential method). can anybody if this is correct or i am doing any mistake while forming the structures, please/ i have attached both the structures with this mail.

4

General Questions and Answers / small clarifications about electrodes

« on: August 13, 2011, 20:00 »

hi

i had created this structure (removed a couple of layers of carbon atoms and used passivate script) but now i am not able to attach electrodes to it

it shows an error "Total width of electrodes may not exceed width of central region"
can you please what is this error about and how to rectify this. i want to attach electrodes to the same structure. i have faced this error a lot times before as well and i dont know when exactly this comes as sometimes i am able to attach electrodes to constricted GNRs

regards
deepak

5

General Questions and Answers / a small doubt in TranSIESTA

« on: August 11, 2011, 12:21 »

Hi

sorry for starting it here but since i could not get help anywhere else about it i thought of asking it here as VNL is also based on SIESTA/TranSIESTA


ts_iohs: BAD DIMENSIONS
and then run terminates

what is this error
it comes just after it starts to read the left electrode dimensions

i found that a file called ts_iohs.h is generated

it contains:

C Dimensions for input to ts_iohs
   parameter (nspin = 1499993)


i checked the buffer atoms no and all and it seems right

what exactly is this TSiohs (i found files going by that name in TBTrans directory)

please help
deepak

6

General Questions and Answers / Re: Error while optimizing a structure

« on: August 6, 2011, 12:51 »

hi

thanks for the link
is there any other way to optimize the structure in 2008.10 version itself as it may take me a few days to go the place where 11.2 version is there

or please point out the mistake in the script i attached

regards
deepak

7

General Questions and Answers / Re: Error while optimizing a structure

« on: August 5, 2011, 11:02 »

hi

is there no way to optimize it here??

and also please tell/ give any link that uses the brenner potential to optimize in 11.2 version
i usually use the optimize block along with ATK-DFT which sometimes takes more than 3 days to optimize some structures

8

General Questions and Answers / Re: Error while optimizing a structure

« on: August 4, 2011, 16:23 »

Hi

this is just to check
now am in a different place where 11.2 version is there
is there any way to do it??

9

General Questions and Answers / Re: Error while optimizing a structure

« on: August 4, 2011, 11:56 »

Hi

i am trying the following structure(in the script) to optimize a structure in 2008.10 version
the run goes on for the whole 100 steps as in the parameters and quits saying maximum no of steps reached

please tell me what am i missing
i included Total Energy and Forces parameters
but i dont know what else have left out

10

General Questions and Answers / Re: Error while optimizing a structure

« on: July 29, 2011, 19:10 »

for some reason i am not able to upload my files
it says "upload folder full"

11

General Questions and Answers / Error while optimizing a structure

« on: July 29, 2011, 19:09 »

Hi

I tried to optimize a structure of ZGNR with some structural defects , it becomes a haphazard structure within first few run only and continues to deteriorate . please someone tell what is wrong with my structure. I followed the procedure given in tutorials for optimization

regards
deepak

12

General Questions and Answers / Three Electrode Configuration

« on: July 16, 2011, 18:15 »

Hi

Is it possible to create a structure that contains a three electrode configuration
does ATK support that type of calculation

13

General Questions and Answers / Re: Problem for ploting bandstructure or transmission

« on: June 29, 2011, 11:39 »

problem 2.
I cant plot any picture, band structure, transmission spetctrum, etc...
select band structure and click Show button then just blank plot pop up.
////


hi even i have the same error when i run it in RHEL but in debian or windows i dont get this prob
if you want to plot it export it and plot it using Grace or Gnuplot or any other such plotting softie

14

General Questions and Answers / Re: Trouble while plotting Bandstructure

« on: June 25, 2011, 08:33 »

yeah... it is Linux (RHEL 5 - Gnome Desktop Environment)

Ctrl + R did no change to the plot

15

General Questions and Answers / Re: Trouble while plotting Bandstructure

« on: June 23, 2011, 18:54 »

Hi

here i am attaching two screenshots showing Transmission Spectra and Conductance plot

The first was taken when the Conductance Plot analyzer windows was in its normal shape. There one can see some plot in the Transmission Spectra plot

The second was taken after maximising the same window. There is nothing on the plot