Magneto-optical evidence for depinning of the Wigner crystal by an electric field

Кукушкин, И. В.; Pulsford, N. J.; Klitzing, K. von; Ploog, K.; Haug, Rolf J.; Koch, S. W.; Тимофеев, В. Б.

doi:10.1103/physrevb.45.4532

Cited by 56 publications

(23 citation statements)

References 13 publications

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“…Extrinsic PL experiments utilise specialized structures, in which a δ-doped layer of acceptors is grown into the GaAs at a certain distance from the Ga 1−x Al x AsGaAs interface 28,29,30 . The recombination studied in extrinsic PL is between a 2D electron and a hole bound to an acceptor in the δ-doped layer.…”

Section: Intrinsic and Extrinsic Plmentioning

confidence: 99%

Optics with Quantum Hall Skyrmions

Portengen

Chapman

Nicopoulos

et al. 1998

Int. J. Mod. Phys. B

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A novel type of charged excitation, known as a Skyrmion, has recently been discovered in quantum Hall systems with filling factor near ν = 1. A Skyrmion-which can be thought of as a topological twist in the spin density of the electron gas-has the same charge as an electron, but a much larger spin. In this review we present a detailed theoretical investigation of the optical properties of Skyrmions. Our results provide means for the optical detection of Skyrmions using photoluminescence (PL) spectroscopy. We first consider the optical properties of Skyrmions in disordered systems. A calculation of the luminescence energy reveals a special optical signature which allows us to distinguish between Skyrmions and ordinary electrons. Two experiments to measure the optical signature are proposed. We then turn to the optical properties of Skyrmions in pure systems. We show that, just like an ordinary electron, a Skyrmion may bind with a hole to form a Skyrmionic exciton. The Skyrmionic exciton can have a lower energy than the ordinary magnetoexciton. The optical signature of Skyrmions is found to be a robust feature of the PL spectrum in both disordered and pure systems.

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Section: Intrinsic and Extrinsic Plmentioning

confidence: 99%

Optics with Quantum Hall Skyrmions

Portengen

Chapman

Nicopoulos

et al. 1998

Int. J. Mod. Phys. B

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“…The phases of the two-dimensional electron system (2DES) in high magnetic field have been a subject of substantial interest recently [1][2][3][4][5][6][7]. Following the discovery of the fractional quantum Hall liquid (FQHL) states there is now very strong evidence for the existence of a Wigner solid (WS) state for both electron [1][2][3][4] and hole [5] systems.…”

Section: New Phases Of the 2d Electron System In The Ultra-quantum LImentioning

confidence: 99%

New phases of the 2D electron system in the ultra-quantum limit observed by cyclotron resonances

et al. 1993

Phys. Rev. Lett.

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Cyclotron resonance on low density, 2D electron systems in the ultra-quantum limit show split and shifted resonances. This demonstrates the presence in the ground state of both spin orientation electrons, whose relative proportion is strongly temperature and occupancy dependent. A critical occupancy of -~ jo divides single-particle behavior in a gaseous phase from the quantum liquid where the resonance positions are temperature and carrier density dependent. The resonances suggest a mixed spin state for some regions of the liquid phase. PACS numbers: 73.20.Dx, 78.20.Ls The phases of the two-dimensional electron system (2DES) in high magnetic field have been a subject of substantial interest recently [1-7]. Following the discovery of the fractional quantum Hall liquid (FQHL) states there is now very strong evidence for the existence of a Wigner solid (WS) state for both electron [1-4] and hole [5] systems. Suggestions have been made that both gas and liquid-crystal phases can exist at intermediate temperatures, or that domains of solid can persist up to temperatures well above the classical melting condition [6]. We report cyclotron resonance studies of the electron system in which we observe strong evidence for the existence of a phase boundary separating gaslike, independent single-particle behavior from a correlated liquid state, and we have clear evidence that at low quantum occupancy the liquid state is comprised of electrons of both spin states of the lowest Landau level, with a preference for spin pairing. By contrast the system appears to become completely spin polarized only at very low densities and low temperatures.The experiment measures cyclotron resonance in a 3 He cryostat with conventional infrared spectroscopy, using both a Fourier spectrometer and a CO2 pumped molecular gas laser. A series of five high mobility GaAs/GaAl-As heterojunctions grown at Philips Research Laboratories, Redhill [7] was studied, with spacer layer thicknesses of 480, 320, 240, 160, and 80 nm, which allowed the carrier concentration to be varied from 1 to 15 x 10 10 cm ~2. In addition, continuous reduction of the density in situ by up to 80% was achieved using above barrier illumination from a HeNe laser with power densities of -10 -7 -10~" 3 W/cm 2 . No difference was detected between data taken at comparable densities either between measurements with different samples or with different illumination conditions. The carrier densities were measured to a precision of -10%, using the total absorption strength of the resonances. These values agreed well with transport data taken at low fields, although it was not usually possible to make electrical measurements on these samples at high magnetic fields. The magnetic field dependences were always measured in the dark, for which the density remained accurately constant, while carrier concentration studies were performed using fixed fields. Figure 1 shows the transmission spectra for a series of magnetic fields for two electron densities, covering the range of occupancies v= j to 7...

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“…Остановимся на влиянии электрического поля на свойства S линии, появляющейся в режиме вигне ровской кристаллизации. Было обнаружено порого вое усиление интенсивности этой линии, которое сопровождалось появлением дополнительного ш у м а и з з а н е с т а б и л ь н о с т и с и г н а л а люминесценции вблизи порога [94]. Указанные особенности объясняются срывом запиннингован ного электрическим полем вигнеровского кристал ла.…”

Section: введение (1) 2 излучательная рекомбинация 2d электронов в unclassified

Magneto-optics of two-dimensional electron systems in the ultraquantum limit: incompressible quantum liquids and the Wigner crystal

Кукушкин¹,

Тимофеев²

1993

Usp. Fiz. Nauk

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Magneto-optical evidence for depinning of the Wigner crystal by an electric field

Cited by 56 publications

References 13 publications

Optics with Quantum Hall Skyrmions

Optics with Quantum Hall Skyrmions

New phases of the 2D electron system in the ultra-quantum limit observed by cyclotron resonances

Magneto-optics of two-dimensional electron systems in the ultraquantum limit: incompressible quantum liquids and the Wigner crystal

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