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Electrons and holes

  1. Dec 20, 2015 #1
    Well here's the problem carbon nanotubes possess a electron - hole symmetry .my question is to what property of CNT'S does this symmetricity attribute to ? in otherwords if we dope this with a material with more electrons / holes what property will change ?
  2. jcsd
  3. Dec 22, 2015 #2
    please help me with this question
  4. Dec 22, 2015 #3


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    I was going to make a comment asking "why would you care since you think holes are "imaginary"?", but I won't!

    (Ooops.. I think I just did).

    First of all, do you know what "electron-hole symmetry" means?

    Secondly, have you looked at the band structure of a carbon nanotube? In particular, have you looked carefully at the bands just above and just below the Fermi energy?

    If you have done both, have you tried to figure out the connection between those two?

  5. Dec 23, 2015 #4
    First of all thanks for the constructive criticism but what i meant to say was the hole itself was a mathematical construction aimed at avoiding the use of negative values for mass . secondly i think i don't know what electron- hole symmetry means neither do i know what fermi energy means because i don't have the mathematical background yet ,so is there anyway of simplifying this for me ?
  6. Dec 23, 2015 #5


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    Then I would strongly suggest that you hold off on your characterization of holes as being "unphysical" and "imaginary". You do not have sufficient knowledge YET to be able to make such a judgement. That's like saying air bubbles in water are "unphysical" and "imaginary".

    Unfortunately, and this is something we encounter many times on here, your question is too advanced for you to understand the answer. This is because, if I explain it to you, than I will end up explaining what I had explained. It will be one step forward, and 3 steps back. You asked why CNTs have electron-hole symmetry, yet you don't know what "electron-hole symmetry" means (which begs the question: "Why would you even be interested to know why CNTs have electron-hole symmetry in the first place?"). And the very foundation of electronic behavior in solids, i.e. the concept of Fermi energy, is extremely vital.

    For now, electron-hole symmetry, to you, means that both the electron and the hole that were created are mirror images of each other, having identical properties such as mobility, mass, etc. with the exception of having opposite charge.

    If you want to know more, than start asking (or googling) topics that are more basic than that. Star by learning what is a "Fermi energy" in metals, and what is a band structure of a solid. Without understanding those FIRST, you will not be able to comprehend why CNTs have electron-hole symmetry.

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