Collective properties of indirect excitons in coupled quantum wells in a random field

Berman, Oleg L.; Lozovik, Yurii E.; Snoke, D. W.; Coalson, Rob D.

doi:10.1103/physrevb.70.235310

Cited by 57 publications

(63 citation statements)

References 56 publications

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“…This density of the superfluid component is defined by the two-particle Green function of weakly interacting excitons. The problem to find the two-particle Green function of the interacting excitons requires one-particle Green function of non-interacting excitons, which is defined by the wave function and energy dispersion of a single exciton [11]. The collective properties and superfluidity of excitons and polaritons in gapped graphene have been studied in Refs.…”

Section: Introductionmentioning

confidence: 99%

Coupling of two Dirac particles

2013

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A study of the formation of excitons as a problem of two Dirac particles in a gapped graphene layer and in two gapped graphene layers separated by a dielectric is presented. In the low-energy limit the separation of the center-of-mass and relative motions is obtained. Analytical solutions for the wave function and energy dispersion for both cases when electron and hole interact via a Coulomb potential are found. It is shown that the energy spectrum and the effective exciton mass are functions of the energy gaps as well as interlayer separation in case of two layer gapped graphene.

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Section: Introductionmentioning

confidence: 99%

Coupling of two Dirac particles

2013

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“…The prediction of superfluidity and BEC of dipolar (indirect) excitons formed by spatially separated electrons and holes in semiconductor coupled quantum wells (CQWs) attracted interest to this system [11][12][13][14][15][16][17][18][19][20]. In the CQWs negative electrons are trapped in a two-dimensional plane, while an equal number of positive holes is located in a parallel plane at a distance D away.…”

Section: Introductionmentioning

confidence: 99%

High-temperature superfluidity of the two-component Bose gas in a transition metal dichalcogenide bilayer

Berman

Kezerashvili

2016

Phys. Rev. B

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The high-temperature superfluidity of two-dimensional dipolar excitons in two parallel TMDC layers is predicted. We study Bose-Einstein condensation in the two-component system of dipolar A and B excitons. The effective mass, energy spectrum of the collective excitations, the sound velocity and critical temperature are obtained for different TMDC materials. It is shown that in the Bogolubov approximation the sound velocity in the two-component dilute exciton Bose gas is always larger than in any one-component. The difference between the sound velocities for two-component and one-component dilute gases is caused by the fact that the sound velocity for a two-component system depends on the reduced mass of A and B excitons, which is always smaller than the individual mass of A or B exciton. Due to this fact, the critical temperature Tc for superfluidity for the twocomponent exciton system in a TMDC bilayer is about one order of magnitude higher than Tc in any one-component exciton system. We propose to observe the superfluidity of two-dimensional dipolar excitons in two parallel TMDC layers, which causes two opposite superconducting currents in each TMDC layer.

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“…The density of the superfluid component n S (T ) for two-dimensional system with the sound spectrum can be estimated as: [32] …”

Section: Superfluidity Of Magnetoexcitons In Bilayer Graphenementioning

confidence: 99%

“…Let us mention that if the interaction of bosons with the random field is stronger, the BEC critical temperature is lower [32]. In this paper we study the superfluidity of magnetoexcitons in bilayer graphene, instability of the system of magnetoexcitons in superlattice formed by many GLs, superfluidity of magnetobiexcitons in graphene superlattice, and BEC of polaritons in GL embedded in optical microcavity in a trap.…”

Section: Introductionmentioning

confidence: 99%

Bose–Einstein condensation of quasiparticles in graphene

2010

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The collective properties of different quasiparticles in various graphene based structures in high magnetic field have been studied. We predict Bose-Einstein condensation (BEC) and superfluidity of 2D spatially indirect magnetoexcitons in two-layer graphene. The superfluid density and the temperature of the Kosterlitz-Thouless phase transition are shown to be increasing functions of the excitonic density but decreasing functions of magnetic field and the interlayer separation. The instability of the ground state of the interacting 2D indirect magnetoexcitons in a slab of superlattice with alternating electron and hole graphene layers (GLs) is established. The stable system of indirect 2D magnetobiexcitons, consisting of pair of indirect excitons with opposite dipole moments, is considered in graphene superlattice. The superfluid density and the temperature of the KosterlitzThouless phase transition for magnetobiexcitons in graphene superlattice are obtained. Besides, the BEC of excitonic polaritons in GL embedded in a semiconductor microcavity in high magnetic field is predicted. While superfluid phase in this magnetoexciton polariton system is absent due to vanishing of magnetoexciton-magnetoexciton interaction in a single layer in the limit of high magnetic field, the critical temperature of BEC formation is calculated. The essential property of magnetoexcitonic systems based on graphene (in contrast, e.g., to a quantum well) is stronger influence of magnetic field and weaker influence of disorder. Observation of the BEC and superfluidity of 2D quasiparticles in graphene in high magnetic field would be interesting confirmation of the phenomena we have described.

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Collective properties of indirect excitons in coupled quantum wells in a random field

Cited by 57 publications

References 56 publications

Coupling of two Dirac particles

Coupling of two Dirac particles

High-temperature superfluidity of the two-component Bose gas in a transition metal dichalcogenide bilayer

Bose–Einstein condensation of quasiparticles in graphene

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