title: Quantum Hall exciton condensation at full spin polarization.
abstract: Using Coulomb drag as a probe, we explore the excitonic phase transition in quantum Hall bilayers at nu(T) = 1 as a function of Zeeman energy E(Z). The critical layer separation (d/l)(c) for exciton condensation initially increases rapidly with E(Z), but then reaches a maximum and begins a gentle decline. At high E(Z), where both the excitonic phase at small d/l and the compressible phase at large d/l are fully spin polarized, we find that the width of the transition, as a function of d/l, is much larger than at small E(Z) and persists in the limit of zero temperature. We discuss these results in the context of two models in which the system contains a mixture of the two fluids.
authors.affiliation: Condensed Matter Physics, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: A D K
authors.initials: AD
authors.lastname: Finck
authors.forename: J P
authors.initials: JP
authors.lastname: Eisenstein
authors.forename: L N
authors.initials: LN
authors.lastname: Pfeiffer
authors.forename: K W
authors.initials: KW
authors.lastname: West