I don't quite see why this magnesium diboride is so
exciting. Its structure must be very simple and there might
be no anisotropic structure along different directions and
its coupling might be still s-wave coupling. BCS's
prediction about Tc is based on the attraction due to the
phonon exchange and the coherent length is about 100nm. And
hence reduce the probability of obtaining HTc
superconductors as the temperature gets high enough and put
the coherent coupling to the edge.
I believe there mig