Finite-momentum condensate of magnetic excitons in a bilayer quantum Hall system

Doretto, R. L.; Smith, C. Morais; Caldeira, A. O.

doi:10.1103/physrevb.86.035326

Cited by 13 publications

(6 citation statements)

References 53 publications

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“…So polaronic excitons in the belt emit a light shift from 472.8 to 475.2 nm with the rising power; this is not different from the wire. The difference lies in the polaronic exciton dominating in the belt, which is much like the magnetic exciton Bose-Einstein condensation [36]. The differences in optical response naturally related themselves in the time and space scales of exciton-exciton, exciton-phonon and carrier-exciton interactions with dimensionality modulation.…”

Section: Resultsmentioning

confidence: 99%

Luminescence and local photonic confinement of single ZnSe:Mn nanostructure and the shape dependent lasing behavior

et al. 2013

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One-dimensional Mn-ZnSe nanostructures with high crystallite quality were synthesized by the CVD method. Transmission electron microscopy was used to study the defect state, crystal lattice and growth direction of as-prepared nanostructures. Raman spectra under varied excitation wavelengths confirmed the dopant modes of Mn(II) and the inhomogeneity. The micro-photoluminescence (PL) spectra of individual nanostructures under CW laser excitation with different powers showed the dominant trapped state emission with periodic multi-peaks. The selected peak mapping indicated that there were many integrated Fabry-Perot cavities and whispering gallery mode cavities within the nanowires/nanoneedles and nanobelts, respectively, which can be accounted for by inhomogeneous optical phases in the Mn-ZnSe nanostructure. The phase may be introduced by both Mn doping and structural relaxation. The micro-PL spectra under nanosecond pulse laser excitation produce low threshold lasing lines near the band edge of Mn-ZnSe nanostructures. The lasing occurs due to the dominant interaction between bound excitons at high density, evidenced by its appearance close to the LO phonon replica. The belts show much stronger lasing emission due to larger 2D coherent space than the wires due to the inhomogeneity induced by the doping process. The different optical behavior with changing excitation pulses may find applications in future photonic devices of II-VI nanostructures.

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Section: Resultsmentioning

confidence: 99%

Luminescence and local photonic confinement of single ZnSe:Mn nanostructure and the shape dependent lasing behavior

et al. 2013

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“…Such a formalism was also applied to study quantum Hall ferromagnetic phases realized in graphene at filling factors ν = 0 and ν = ±1 20 and to describe the Bose-Einstein condensate of magnetic excitons realized in a bilayer quantum Hall system at total filling factor ν T = 1. 21,22…”

Section: Introductionmentioning

confidence: 99%

Flat-band ferromagnetism and spin waves in topological Hubbard models

Doretto¹,

Goerbig²

2015

Phys. Rev. B

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We study the flat-band ferromagnetic phase of a topological Hubbard model within a bosonization formalism and, in particular, determine the spin-wave excitation spectrum. We consider a square lattice Hubbard model at 1/4-filling whose free-electron term is the π-flux model with topologically nontrivial and nearly flat energy bands. The electron spin is introduced such that the model either explicitly breaks time-reversal symmetry (correlated flat-band Chern insulator) or is invariant under time-reversal symmetry (correlated flat-band Z2 topological insulator). We generalize for flat-band Chern and topological insulators the bosonization formalism [Phys. Rev. B 71, 045339 (2005)] previously developed for the two-dimensional electron gas in a uniform and perpendicular magnetic field at filling factor ν = 1. We show that, within the bosonization scheme, the topological Hubbard model is mapped into an effective interacting boson model. We consider the boson model at the harmonic approximation and show that, for the correlated Chern insulator, the spin-wave excitation spectrum is gapless while, for the correlated topological insulator, gapped. We briefly comment on the possible effects of the boson-boson (spin-wave-spin-wave) coupling.

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“…In the limit d → 0, the ground state of the ν T = 1 bilayer is known to be the Halperin (111) state [9,16,24]. Meanwhile, the ground state of the system at intermediate layer distances 0 < d/ < κ c2 is still unsettled [29][30][31][32][33][34][35][36][37][38][39][40], which is a major obstacle in understanding the transition from exciton superfluid to CFL. Numerical calculations are employed to reveal the nature of the ground state [37][38][39][40][41][42][43], and a charge gap closing is indeed observed at d/ ≈ 1.8.…”

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confidence: 99%

Wave Function and Emergent SU(2) Symmetry in the νT=1 Quantum Hall Bilayer

Lian

Zhang

2018

Phys. Rev. Lett.

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We propose a trial wave function for the quantum Hall bilayer system of total filling factor ν_{T}=1 at a layer distance d to magnetic length ℓ ratio d/ℓ=κ_{c1}≈1.1, where the lowest charged excitation is known to have a level crossing. The wave function has two-particle correlations, which fit well with those in previous numerical studies, and can be viewed as a Bose-Einstein condensate of free excitons formed by composite bosons and anticomposite bosons in different layers. We show the free nature of these excitons indicating an emergent SU(2) symmetry for the composite bosons at d/ℓ=κ_{c1}, which leads to the level crossing in low-lying charged excitations. We further show the overlap between the trial wave function, and the ground state of a small size exact diagonalization is peaked near d/ℓ=κ_{c1}, which supports our theory.

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Finite-momentum condensate of magnetic excitons in a bilayer quantum Hall system

Cited by 13 publications

References 53 publications

Luminescence and local photonic confinement of single ZnSe:Mn nanostructure and the shape dependent lasing behavior

Luminescence and local photonic confinement of single ZnSe:Mn nanostructure and the shape dependent lasing behavior

Flat-band ferromagnetism and spin waves in topological Hubbard models

Wave Function and Emergent SU(2) Symmetry in the νT=1 Quantum Hall Bilayer

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