Making Cooper Pairs of Cooper Pairs?

1. May 18, 2012

calvinjhfeng

I wonder do cooper pairs make cooper pair in superconductors, like two cooper pairs pair up to make another cooper pair?
I am still unclear on how this mechanism work to produce the effect of zero electrical resistance.

I supposed all the electrons are paired up in cooper pair and these cooper pairs should be paired up too. That way everything moves forward (in a supercurrent) without any scattering or loss of energy due to collision.

2. May 18, 2012

Staff Emeritus
Electrons are fermions. Cooper pairs are bosons. The forces between them is simply different.

3. May 19, 2012

vkroom

Cooper pairs are *dynamical* pairing of fermions. Cooper pairs being bosons ultimately condense in momentum space. There is not much use in considering pairs of bosons with $\pm \vec{k}{}$ since most of them will end up having the same momentum due to condensation.

4. May 21, 2012

calvinjhfeng

I have very little understanding of the properties of elementary particles. So the idea is that once electrons formed pairs, they become bosons and from that point on, extra bonding is unnecessary to avoid scattering effect?

5. May 22, 2012

vkroom

The condensation of Cooper pairs is a property of their statistics (Bose-Einstein ). It has nothing to do with interactions between them. In reality I think one requires some sort of repulsive interactions for condensation to occur. But at an elementary level one may think of condensation of Cooper pairs as solely due to their bosonic nature.