A complete laboratory for transport studies of electron-hole interactions in GaAs/AlGaAs ambipolar bilayers

Cumis, Ugo Siciliani de; Waldie, J.; Croxall, A. F.; Taneja, Deepyanti; Llandro, J.; Farrer, I.; Beere, Harvey E.; Ritchie, D. A.

doi:10.1063/1.4976505

Cited by 9 publications

(1 citation statement)

References 41 publications

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“…The lifetime of these excitons can be increase in an electron-hole bilayer system (EHBL), which consists of two parallel layers, separated by a distance d, where electrons are confined to one layer and holes are in the other. The EHBL system can be realized in double quantum well (DQW) structures such as the GaAs/AlGaAs heterostructure [1][2][3][4][5][6][7] and bilayer graphene [8][9][10][11]. By applying an external electric field, one can minimize the overlapping of the wave functions of the electron and hole, which reduces the electron-hole recombination rate and hence increases the average lifetime of excitons as compared to direct excitons in the excited semiconductor.…”

Section: Introductionmentioning

confidence: 99%

Phase diagram of a symmetric electron–hole bilayer system: a variational Monte Carlo study

Sharma

Saini²,

Bahuguna³

2018

J. Phys.: Condens. Matter

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We study the phase diagram of a symmetric electron-hole bilayer system at absolute zero temperature and in zero magnetic field within the quantum Monte Carlo approach. In particular, we conduct variational Monte Carlo simulations for various phases, i.e. the paramagnetic fluid phase, the ferromagnetic fluid phase, the anti-ferromagnetic Wigner crystal phase, the ferromagnetic Wigner crystal phase and the excitonic phase, to estimate the ground-state energy at different values of in-layer density and inter-layer spacing. Slater-Jastrow style trial wave functions, with single-particle orbitals appropriate for different phases, are used to construct the phase diagram in the (r , d) plane by finding the relative stability of trial wave functions. At very small layer separations, we find that the fluid phases are stable, with the paramagnetic fluid phase being particularly stable at [Formula: see text] and the ferromagnetic fluid phase being particularly stable at [Formula: see text]. As the layer spacing increases, we first find that there is a phase transition from the ferromagnetic fluid phase to the ferromagnetic Wigner crystal phase when d reaches 0.4 a.u. at r = 20, and before there is a return to the ferromagnetic fluid phase when d approaches 1 a.u. However, for r < 20 and [Formula: see text] a.u., the excitonic phase is found to be stable. We do not find that the anti-ferromagnetic Wigner crystal is stable over the considered range of r and d. We also find that as r increases, the critical layer separations for Wigner crystallization increase.

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