Speaker
Boris Spivak (U. of Washington)
(University of Washington)
Description
he Pfaffian phase of electrons in the proximity of a
half-filled Landau level is understood to be a p+ip
superconductor of composite fermions. We consider the
properties of this paired quantum Hall phase when the
pairing scale is small, i.e. in the weak-coupling, BCS,
limit, where the coherence length is much larger than the
charge screening length. We find that, as in a Type I
superconductor, the vortices attract so that, upon varying
the magnetic field from its magic value at \nu=5/2, the
system exhibits Coulomb frustrated phase separation. We
propose that the weakly and strongly coupled Pfaffian states
exemplify a general dichotomy between Type I and Type II
quantum Hall fluids.
