question on validation

[rose]

Hi ,
regarding the tutorial:
http://docs.quantumwise.com/tutorials/low_level_entities/low_level_entities.html

I am really interested in the impedance response of CNT that mentioned there.

Does the wide-band limit is validated in high frequency? If yes why? If no up to which value we can say that the wide band limit is valid?
thanks
Rose

[Daniele Stradi]

Hi Rose,

As mentioned in the paper from which the model is taken (PRB 81, 115448 (2010)):

"Here, “low-frequency” means that omega is much smaller than an inverse of dwell time d−1 that an electron stays inside the central device region of a
SWNT. For example, such a low-frequency regime is estimated as omega<1 THz for 1-microm-length metallic SWNTs."

Regards,
Daniele.

[rose]

Hi
Thanks for your answer. Yes, I got that part from the paper, however, the Figure in this tutorial is up to 1eV which as I got is far more than 1THz. So I think the question is still stand. Does WBL still correct in this 1eV energy?
Thanks
Rose

[Daniele Stradi]

I think this is more a scientific discussion rather than a discussion on ATK and its usage, so this might not be the appropriate forum to ask.

What I read from the sentence above, is that the question on whether the approximation is valid or not depends on the length of the CNT system. The approximation should be valid for frequencies up to 1 eV for CNT systems up 1 micrometer.