Quasicondensation of Bilayer Excitons in a Periodic Potential

Lagoin, Camille; Suffit, Stéphan; West, K. W.; Baldwin, K. W.; Pfeiffer, L. N.; Holzmann, Markus; Dubin, F.

doi:10.1103/physrevlett.126.067404

Cited by 15 publications

(13 citation statements)

References 36 publications

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“…The anticipated long lifetime of electrons in the high levels of the quantum well is reminiscent of dark excitons, which have a long lifetime because spin-mismatch does not allow radiative recombination. [6] Here, it would be the small overlap of the wave functions of the holes and electrons in the quantum well that leads to long lifetimes. Long lifetimes of electrons and holes have also been achieved by spatially separating them in a lateral electric field.…”

Section: Discussionmentioning

confidence: 99%

“…[5] In the case of "dark" excitons the recombination rate is further reduced by a spin mismatch to the photons and signatures of BEC have been observed. [6] An alternative route to long lifetimes is offered by exciton-polaritons where excitons are strongly coupled to light in an optical resonator leading to quasi-particles showing clear signatures of BEC. [7,8] Quasi-excitons with infinitely long lifetimes form in electron or hole bilayers with two half-filled Landau levels in a quantizing magnetic field.…”

Section: Introductionmentioning

confidence: 99%

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Capacitance and conductance oscillations from electron tunneling into high energy levels of a quantum well in a p-i-n diode

Parolo,

Lupatini,

Külah

et al. 2021

Preprint

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Two-dimensional electron and hole gases separated by a few nm from each other are produced in p-i-n diodes based upon MBE-grown GaAs/AlGaAs heterostructures. At such interlayer distances, the exciton formation and possibly Bose-Einstein condensation (BEC) is expected. We measure the capacitance between the layers and find it to oscillate as a function of the bias voltage. The peak values exceed the geometric capacitance by up to a factor of two. The surprisingly regular periods of the oscillations are of the order of 10 to 30 mV and scale linearly with the inverse of the thickness between 60 and 150 nm of the GaAs layer placed between the barrier and the p-doped AlGaAs. The oscillations are related to the resonant electron tunneling into high energy levels of this GaAs layer acting as a quantum well. We suggest that long lifetimes of the electrons in these levels are the origin of the large peak values of the capacitance. The possible relation of the capacitance oscillations with BEC is discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Capacitance and conductance oscillations from electron tunneling into high energy levels of a quantum well in a p-i-n diode

Parolo,

Lupatini,

Külah

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…4 and In the case of GaAs heterostructures, it corresponds to 200-400 nm. That is the maximum resolution achieved in photoluminescence experiments with spatially indirect excitons [66]. At lower resolutions, one can also observe stationary waves, but only at a large distance from the obstacle.…”

Section: Dynamical Approachmentioning

confidence: 93%

Stationary waves in a superfluid gas of electron-hole pairs in bilayers

Fil,

Shevchenko

2021

Preprint

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Stationary waves in the condensate of electron-hole pairs in the n − p bilayer system are studied. The system demonstrates the transition from a uniform (superfluid) to a nonuniform (supersolid) state. The precursor of this transition is the appearance of the roton-type minimum in the collective mode spectrum. Stationary waves occur in the flow of the condensate past an obstacle. It is shown that the roton-type minimum manifests itself in a rather complicated stationary wave pattern with several families of crests which cross one another. It is found that the stationary wave pattern is essentially modified under variation in the density of the condensate and under variation in the flow velocity. It is shown that the pattern is formed in the main part by shortwave modes in the case of a point obstacle. The contribution of longwave modes is clearly visible in the case of a weak extended obstacle, where the stationary wave pattern resembles the ship wave pattern.

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“…First studies have already investigated the possibility of superfluid phase formation in TMD heterobilayers [19,20], explor-ing the transition between superfluid and Mott state. Realizations of BH systems have also been studied with IX in gated double quantum-well structures [21][22][23], where the lattice potential was realized by patterned, externally applied electric fields. In comparison, in twisted TMD heterobilayers the moiré potential emerges naturally from the varying stacking order in the twisted material layers, where the degree of localization can be altered via the twist angle.…”

Section: Introductionmentioning

confidence: 99%

Moiré-Bose-Hubbard model for interlayer excitons in twisted transition metal dichalcogenide heterostructures

Götting,

Lohof,

Gies

2022

Preprint

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In bilayers of semiconducting transition metal dichalcogenides, the twist angle between layers can be used to introduce a highly regular periodic potential modulation on a length scale that is large compared to the unit cell. In such structures, correlated states can emerge, in which excitons in the heterostructure are strongly localized to the potential minima due to exciton-exciton interactions. We explore the transition between Mott and extended exciton phases in terms of a moiré-Bose-Hubbard Hamiltonian. Hopping and on-site interaction parameters are obtained from a Wannier representation of the interlayer-exciton wave functions, and a non-local Rytova-Keldysh model is used to attribute for the dielectric screening of excitons in the two-dimensional material. For sufficiently small exciton concentrations our model predicts the emergence of Mott-insulating states, establishing twisted TMD heterostructures as possible quantum simulators for bosonic many-body systems.

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Quasicondensation of Bilayer Excitons in a Periodic Potential

Cited by 15 publications

References 36 publications

Capacitance and conductance oscillations from electron tunneling into high energy levels of a quantum well in a p-i-n diode

Capacitance and conductance oscillations from electron tunneling into high energy levels of a quantum well in a p-i-n diode

Stationary waves in a superfluid gas of electron-hole pairs in bilayers

Moiré-Bose-Hubbard model for interlayer excitons in twisted transition metal dichalcogenide heterostructures

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