title: Strong enhancement of drag and dissipation at the weak- to strong-coupling phase transition in a bilayer system at a total Landau level filling nu = 1.
abstract: We consider a bilayer electronic system at a total Landau level filling factor nu = 1, and focus on the transition from the regime of weak interlayer coupling to that of the strongly coupled (1,1,1) phase (or "quantum Hall ferromagnet"). Making the assumption that in the transition region the system is made of puddles of the (1,1,1) phase embedded in a bulk of the weakly coupled state, we show that the transition is accompanied by a strong increase in longitudinal Coulomb drag that reaches a maximum of approximately h/2e(2). In that regime the longitudinal drag increases with decreasing temperature.
authors.affiliation: Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Ady
authors.initials: A
authors.lastname: Stern
authors.forename: B I
authors.initials: BI
authors.lastname: Halperin