Two-dimensional snowflake trap for indirect excitons

Kuznetsova, Y. Y.; Andreakou, P.; Hasling, M. W.; Leonard, J. R.; Calman, E. V.; Butov, L. V.; Hanson, M.; Gossard, A. C.

doi:10.1364/ol.40.000589

Cited by 14 publications

(10 citation statements)

References 27 publications

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“…One possibility seems to position the CQW close to the back-contact and to utilize a resonant excitation. Another possibility to overcome the problem of excess charge carriers at the trap-edges seems to be the use of many gates [32] where the interplay of all gates form the overall electrostatic traps in the direction of [78]. For two respective neighboring gates, the gate voltage needs to be small enough such that the IXs are not dissociated.…”

Section: Discussionmentioning

confidence: 99%

On the parabolicity of dipolar exciton traps and their population of excess charge carriers

et al. 2019

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We study spatially trapped ensembles of dipolar excitons in coupled quantum wells by means of photoluminescence and photocurrent spectroscopy. The photogenerated excitons are confined in very clean GaAs double quantum well structures and electrostatically trapped by local gate electrodes. We find that the common approach of electrostatic trap geometries can give rise to an in-plane imbalance of charge carriers especially when an over-barrier excitation is utilized. The excess charge carriers can give rise to an effective parabolic confinement potential for the excitons. In photoluminescence spectra, we identify the emission of both neutral indirect excitons and states influenced by the excess charge carrier density. We find that the charge imbalance in the excitonic ensemble strongly influences the radiative lifetimes of both. Our findings shine a new light on the properties of trapped dipolar exciton ensembles. This is of significant relevance to common interpretations of experimental results in terms of signatures for the formation of 'dark' and 'gray' excitonic condensates.

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Section: Discussionmentioning

confidence: 99%

On the parabolicity of dipolar exciton traps and their population of excess charge carriers

et al. 2019

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“…To explore the collective phases accessible to dipolar excitons, GaAs double quantum wells provide an experimental toy model system, since excitons are then possibly manipulated in a regime of homogeneous broadening [11], and spatially confined in on-demand potential landscapes [12][13][14][15][16][17]. Using these degrees of freedom, we have recently mapped out the quasicondensation crossover of bilayer excitons in boxlike trapping potentials [11,18,19], determining the excitons' equation of state and density fluctuations, and correlated these to the degree of spatial and temporal coherence at subkelvin temperatures.…”

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confidence: 99%

Quasicondensation of Bilayer Excitons in a Periodic Potential

et al. 2021

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We study two-dimensional excitons confined in a lattice potential, for high fillings of the lattice sites. We show that a quasicondensate is possibly formed for small values of the lattice depth, but for larger ones the critical phase-space density for quasicondensation rapidly exceeds our experimental reach, due to an increase of the exciton effective mass. On the other hand, in the regime of a deep lattice potential where excitons are strongly localized at the lattice sites, we show that an array of phase-independent quasicondensates, different from a Mott insulator, is realized.

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“…This implies that dipolar excitons have a potential energy controlled by the amplitude of the electric field applied orthogonally to the bilayer. By engineering a spatially inhomogeneous electric field in the plane of a GaAs double quantum well, typically using a set of gate electrodes deposited at the surface of a fieldeffect device embedding a GaAs bilayer, a rich variety of trapping potentials have been demonstrated [11][12][13][14], as well as devices where excitonic transport is controlled [15][16][17][18].…”

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confidence: 99%

Microscopic lattice for two-dimensional dipolar excitons

et al. 2020

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We report a two-dimensional artificial lattice for dipolar excitons confined in a GaAs double quantum well. Exploring the regime of large fillings per lattice site, we verify that the lattice depth competes with the magnitude of excitons repulsive dipolar interactions to control the degree of localisation in the lattice potential. Moreover, we show that dipolar excitons radiate a narrow-band photoluminescence, with a spectral width of a few hundreds of µeV at 340 mK, in both localised and delocalised regimes. This makes our device suitable for explorations of dipolar excitons quasicondensation in a periodic potential.

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Two-dimensional snowflake trap for indirect excitons

Cited by 14 publications

References 27 publications

On the parabolicity of dipolar exciton traps and their population of excess charge carriers

On the parabolicity of dipolar exciton traps and their population of excess charge carriers

Quasicondensation of Bilayer Excitons in a Periodic Potential

Microscopic lattice for two-dimensional dipolar excitons

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