Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can BCS theory explain type-II superconductor?

  1. Oct 9, 2014 #1
    I know that BCS theory cannot explain high Tc superconductor.
    Most high Tc superconductors belong to type-II ones.
    Can BCS theory explain type-II conventional superconductor?
    How to predict high Hc2 and low Hc1 for type-II conventional superconductor in BCS theory?
  2. jcsd
  3. Oct 9, 2014 #2


    Staff: Mentor

  4. Oct 9, 2014 #3


    User Avatar
    Science Advisor
    Education Advisor

    Nope! Understanding the mechanisms behind high Tc superconductivity remains one of the biggest problems in solid state physics (my solid state lecturer described it as "insta-nobel worthy").

    There are two main theories, resonating-valence-bond theory and pairing in mediated by short-range spin waves known as "paramagnons". The latter has more support, IIRC.

    Further reading: http://link.springer.com/chapter/10.1007/0-306-47081-0_7
  5. Oct 10, 2014 #4


    User Avatar
    Science Advisor

    To my knowledge, the theory of type II superconductors was developed to a high degree by the russian school around Gorkov and Abrikosov, who also received the Nobel prize for that work a few years ago.
    With the original theory of BCS, it was not completely clear as to whether magnetic fields can be described correctly and in a gauge invariant way. The Gorkov equations maintained gauge invariance explicitly so that a detailed treatment of magnetic fields in superconductors became possible. However, the Gorkov equations describe the same physics as BCS, though in a more elegant way. So, yes, BCS theory is able to describe also type II superconductors.
  6. Oct 10, 2014 #5


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    This is misleading. There ARE Type II conventional superconductors, and these are not the high-Tc superconductors.

    As DrDu stated, there are "extensions" to the BCS theory that takes into account the existence of Type II superconductors. This is not unusual or unexpected, since the original BCS theory was to account only for "weak-coupling" superconductors. Strong-coupling superconductors, such as lead, required further tweaks to BCS theory.

  7. Oct 12, 2014 #6


    User Avatar
    Science Advisor
    Education Advisor

    Yes, I totally misread the OP. My apologies!

    ETA: My response makes sense if the question was "Can BCS explain high Tc superconductors?" Which it clearly wasn't.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook