title: Dissipationless transport in low-density bilayer systems
abstract: In a bilayer electronic system the layer index may be viewed as the z component of an isospin- 1 / 2. An XY isospin-ordered ferromagnetic phase was observed in quantum Hall systems and is predicted to exist at zero magnetic field at low density. This phase is a superfluid for opposite currents in the two layers. At B = 0 the system is gapless but superfluidity is not destroyed by weak disorder. In the quantum Hall case, weak disorder generates a random gauge field which probably does not destroy superfluidity. Experimental signatures include Coulomb drag and collective mode measurements.
authors.affiliation: Department of Condensed Matter Physics, Weizmann Institute, Rehovot 76100, Israel.
authors.initials: A
authors.lastname: Stern
authors.lastname: Das Sarma S
authors.initials: MP
authors.lastname: Fisher
authors.initials: SM
authors.lastname: Girvin