Topics

1

General Questions and Answers / Defects creation in Carbon Nanotubes

« on: September 18, 2009, 20:31 »

Hi all, I tried to create defects in Carbon Nanotubes. Here is what I did: First, drop the CNT.vnl into Bulk Builder and repeat it in Z-axis. Then select the atoms to delete or replace them by other element.

Please advise me if this is correct or not, and if we have to do the structure optimization after the defects are created. Thank you very much.

2

General Questions and Answers / chemical bond

« on: September 12, 2009, 16:31 »

For a two-probe system, after the geometry optimization, how to estimate if a chemical bonding is formed at the interfaces? Thank you very much.

3

General Questions and Answers / k value on Transmission coefficent

« on: July 27, 2009, 21:07 »

Dear all,

The k value for transmission coefficient calculation is usually taken between -0.5 to 0.5. Anyone can give more details why k is at this value range? Thank you.

Cherry

4

General Questions and Answers / two-probe system optimization

« on: July 17, 2009, 16:21 »

Sorry to bring up this topic again.
I tried to optimize a two-probe system using the methods supplied by ATK/VNL. Although the atomic force is getting smaller and smaller, while the geometry is dramatically distorted (which is not supposed to be). It was suggested that calculating the total energy versus the distance is the best way using ATK/VNL. Is that correct?
Thank you.

5

General Questions and Answers / question on transmission coefficient

« on: July 16, 2009, 23:17 »

hi, I have one question due to the transmission coefficient. My result of transmission coefficient of a two-probe system shows that the coefficient value can be larger than 1 at some energy levels. Although it says that T(k)>1 if several channels contribute to the transport at the same energy. However, based on the physical meaning (or definition) , this value should be always between o and 1.
Anyone can help me to understand this better? Thank you very much.

cherry