Experimental Progress towards Probing the Ground State of an Electron-Hole Bilayer by Low-Temperature Transport

Gupta, K. Das; Croxall, A. F.; Waldie, J.; Nicoll, C. A.; Beere, Harvey E.; Farrer, I.; Ritchie, D. A.; Pepper, M.

doi:10.1155/2011/727958

Cited by 25 publications

(21 citation statements)

References 78 publications

(145 reference statements)

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“…It is also possible to create devices with oppositely doped layers, the so-called electron-hole bilayers (Das Gupta et al, 2011;Keogh et al, 2005). Coulomb drag measurements in these systems Seamons et al, 2009) do not provide a direct evidence of interlayer coherence, but nevertheless demonstrate an upturn in ρ D as the temperature is lowered below 1K.…”

Section: B Interlayer Exciton Formationmentioning

confidence: 99%

Coulomb drag

2016

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Coulomb drag is a transport phenomenon whereby long-range Coulomb interaction between charge carriers in two closely spaced but electrically isolated conductors induces a voltage (or, in a closed circuit, a current) in one of the conductors when an electrical current is passed through the other. The magnitude of the effect depends on the exact nature of the charge carriers and microscopic, many-body structure of the electronic systems in the two conductors. Drag measurements have become part of the standard toolbox in condensed matter physics that can be used to study fundamental properties of diverse physical systems including semiconductor heterostructures, graphene, quantum wires, quantum dots, and optical cavities.

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Section: B Interlayer Exciton Formationmentioning

confidence: 99%

Coulomb drag

2016

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“…[29]. Probing the ground state of an electron-hole double layer by low temperature transport was experimentally performed [30], and the various experimental studies of excitonic phases in CQWs were described in Ref. [31].…”

Section: Introductionmentioning

confidence: 99%

Electron-hole superfluidity controlled by a periodic potential

et al. 2019

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We propose to control of an electron-hole superfluid in semiconductor coupled quantum wells and double layers of two-dimensional (2D) material by an external periodic field. This can either be created by the gates periodically located and attached to the quantum wells or double layers of 2D material or by the Moiré pattern of two twisted layers. The dependence of the electron-hole pairing order parameter on the temperature, the charge carrier density, and the gate parameters is obtained by minimization of the mean-field free energy. The second order phase transition between superfluid and electron-hole plasma, controlled by the external periodic gate field, is analyzed for different parameters.

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“…[1] Other systems have been investigated, such as electron-hole bilayers with very small electron-hole separations at oxide interfaces [2,3] and bilayer graphene systems with approximately equal electron and hole masses. [4] These systems are expected to exhibit rich phase diagrams with Fermi fluid, excitonic superfluid, biexcitonic, and charge density wave phases.…”

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confidence: 99%

Excitons and biexcitons in symmetric electron-hole bilayers

Maezono

Ríos²,

Ogawa

et al. 2013

Phys. Rev. Lett.

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Symmetric electron-hole bilayer systems have been studied at zero temperature using the diffusion quantum Monte Carlo method. A flexible trial wave function is used that can describe fluid, excitonic and biexcitonic phases. We calculate condensate fractions and pair correlation functions for a large number of densities rs and layer separations d. At small d we find a one-component fluid phase, an excitonic fluid phase, and a biexcitonic fluid phase, and the transitions among them appear to be continuous. At d = 0, excitons appear to survive down to about rs = 0.5 a.u., and biexcitons form at rs > 2.5 a.u. [4] These systems are expected to exhibit rich phase diagrams with Fermi fluid, excitonic superfluid, biexcitonic, and charge density wave phases. [5][6][7] We have studied the simplest possible such model system, with equal electron and hole populations and equal masses, and parallel infinitely-thin twodimensional layers of variable separation and carrier density. It is important to establish the behavior of this simple system before more complicated cases such as those of unequal electron and hole masses [8] and/or unequal electron and hole densities [9] can be tackled with confidence. Further work will be required to study more realistic systems with anisotropic masses, finite well widths and depths, interface roughness, etc. We consider paramagnetic, symmetric, electron-hole bilayers consisting of N up-and down-spin electrons and holes of equal masses, m e = m h , where the distance between the two parallel layers is d. Hartree atomic units are used throughout ( = |e| = m e = 4πǫ 0 = 1). The Hamiltonian of the infinite system iŝwhere e i and h j are the in-plane position vectors of the ith electron and the jth hole. We use finite simulation cells subject to periodic boundary conditions, and the Coulomb sums are evaluated using two-dimensional Ewald sums.[13] Our results have been obtained with N = 29 particles of each type, giving a total of 116 particles, although we have also simulated the system with N = 57, corresponding to 228 particles, to investigate finite size effects, which we find to be small. The parameters that define the system are d and the in-layer density parameter r s = a/ √ 2πN , where a is the side of the square simulation cell. The d parameter controls the interaction between layers, while r s controls the interaction within the layers. In this paper we focus on the density range r s < 10 a.u., and we have not considered the very low density regime within which Wigner crystallization is favorable. [5,6] At large d the electron and hole layers become decoupled and the results for each layer tend towards those for the two-dimensional electron gas, [14][15][16] and when inter-layer and intra-layer interactions become comparable, i.e., at d r s , a paired phase is expected. It has been shown that biexciton formation is energetically favorable at low densities when d < 0.38 a.u. [17,18] Biexciton formation is expected to be suppressed at high densities, and this has been estimated to occur f...

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Experimental Progress towards Probing the Ground State of an Electron-Hole Bilayer by Low-Temperature Transport

Cited by 25 publications

References 78 publications

Coulomb drag

Coulomb drag

Electron-hole superfluidity controlled by a periodic potential

Excitons and biexcitons in symmetric electron-hole bilayers

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