Answer to in
class question: Does electromigration occur in superconductors [like it
does in ordinary metallic conductors when the current density is very high]?
Answer from Prof. Ted Van Duzer, UCB:
“The reason there is lossless (dc) current flow in a
superconductor is that there is
no scattering of the electron
pair fluid; therefore, electromigration is avoided. Not all the
conduction electrons are paired at nonzero temperatures but (for dc) there is no electric
field to accelerate the unpaired electr
ons. It is different for ac since accelerating fields
acting on the unpaired electrons do appear in the superconductor; still I have never heard
that they cause electromigration.
There are several failure phenomena but not electromigration to my knowledg