title: Formation mechanism and low-temperature instability of exciton rings.
abstract: The macroscopic rings observed in the photoluminescence patterns of excitons in coupled quantum wells are explained by a mechanism of carrier imbalance, transport, and recombination. The rings originate from the spatial separation of p and n carriers, and occur at the interface of the p and n domains, where excitons are generated. We explore the states of excitons in the ring over a range of temperatures down to 380 mK and report a transition of the ring into a periodic array of aggregates, a new low-temperature ordered exciton state.
authors.affiliation: Materials Sciences Division, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: L V
authors.initials: LV
authors.lastname: Butov
authors.forename: L S
authors.initials: LS
authors.lastname: Levitov
authors.forename: A V
authors.initials: AV
authors.lastname: Mintsev
authors.forename: B D
authors.initials: BD
authors.lastname: Simons
authors.forename: A C
authors.initials: AC
authors.lastname: Gossard
authors.forename: D S
authors.initials: DS
authors.lastname: Chemla