Oscillations in the acousto-electric proximity coupling to a 2D electron gas

Schenstrom, A.; Qian, Y. J.; Xu, Minfeng; Baum, H. P.; Levy, M.; Sarma, Bimal K.

doi:10.1016/0038-1098(88)90376-6

Cited by 28 publications

(24 citation statements)

References 11 publications

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“…Let us now analyze Γ as a function of σ xx in accordance with (4). If the conductivity is high, then (4πσ xx /vε s )r(k, a) ≫ 1 (5) and Γ ∼ σ xx ;if (for low conductivity)…”

Section: Analysis Of the Experimental Datamentioning

confidence: 99%

“…The effective value of a can be determined from acoustic measurements by investigating the frequency dependence of the maximum value of the absorption coefficient Γ. For the same placement of the sample, i.e., for the same value of a but different SAW frequencies, we obtain [see Eqs (4) and (7)]…”

Section: Analysis Of the Experimental Datamentioning

confidence: 99%

“…since Γ(H) is determined according to (4). As indicated above, the ratio σ dc xx (H max )/σ dc xx (H) is calculated from the components ρ xx (H) and ρ xy (H) of the resistivity tensor which are measured for this sample.…”

Section: Analysis Of the Experimental Datamentioning

confidence: 99%

“…On this basis, it is helpful to extend the acoustic method of investigating rf conductivity to semiconductor structures with a 2DEG. The interaction of surface acoustic waves (SAWs) with two-dimensional electrons was first observed in GaAs/AlGaAs type heterostructures [4,5]. It was shown that the SAW energy is absorbed as a result of this interaction, and the magnitude of the absorption is determined by the conductivity of the 2DEG.…”

Section: Introductionmentioning

confidence: 99%

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Electron localization in sound absorption oscillations in the quantum Hall effect regime

et al. 1997

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The absorption coefficient for surface acoustic waves in a piezoelectric insulator in contact with a GaAs/AlGaAs heterostructure (with two-dimensional electron mobility µ = 1.3 × 10 5 cm 2 /V · s) at T =4.2K) via a small gap has been investigated experimentally as a function of the frequency of the wave, the width of the vacuum gap, the magnetic field, and the temperature. The magnetic field and frequency dependencies of the high-frequency conductivity (in the region 30-210 MHz) are calculated and analyzed. The experimental results can be explained if it assumed that there exists a fluctuation potential in which current carrier localization occurs. The absorption of the surface acoustic waves in an interaction with two-dimensional electrons localized in the energy "tails" of Landau levels is discussed.

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“…Let us now analyze Γ as a function of σ xx in accordance with (4). If the conductivity is high, then (4πσ xx /vε s )r(k, a) ≫ 1 (5) and Γ ∼ σ xx ;if (for low conductivity)…”

Section: Analysis Of the Experimental Datamentioning

confidence: 99%

Section: Analysis Of the Experimental Datamentioning

confidence: 99%

Section: Analysis Of the Experimental Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Electron localization in sound absorption oscillations in the quantum Hall effect regime

et al. 1997

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“…From an experimental point of view, these conditions are satisfied in a dot of size L ≃ 1 µm, patterened in an electron gas with a low mobility (µ ≃ 10 4 cm 2 /Vs) corresponding to l ≃ 100 nm. So, except for the shortest SAW's used in recent experiments, [12][13][14][15]10,16 ql is indeed small. This paper is organized in the following way.…”

Section: Introductionmentioning

confidence: 99%

Elastic scattering and absorption of surface acoustic waves by a quantum dot

1997

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We study theoretically the piezoelectric interaction of a surface acoustic wave (SAW) with a two-dimensional electron gas confined to an isolated quantum dot. The electron motion in the dot is diffusive. The electron-electron interaction is accounted for by solving the screening problem in real space. Since the screening in GaAs/Al x Ga 1−x As heterostructures is strong, an approximate inversion of the dielectric function ǫ(r, r ′ ) can be utilized, providing a comprehensive qualitative picture of the screened SAW potential and the charge redistribution in the dot. We calculate the absorption and the scattering cross-sections for SAW's as a function of the area of the dot, A, the sound wave vector, q, and the diffusion coefficient D of the electrons. Approximate analytical expressions for the cross-sections are derived for all cases where the quantities q 2 A and Aω/D are much larger or smaller than unity; ω is the SAW frequency. Numerical results which include the intermediate regimes and show the sample-specific dependence of the cross-sections on the angles of incidence and scattering of surface phonons are discussed. The weak localization corrections to the cross-sections are found and discussed as a function of a weak magnetic field, the frequency, and the temperature. Due to the absence of current-carrying contacts, the phase coherence of the electron motion, and in turn the quantum corrections, increase as the size of the dot shrinks. This shows that scattering and absorption of sound as noninvasive probes may be advantageous in comparison to transport experiments for the investigation of very small electronic systems.

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The Nonlinear Effects in 2DEG Conductivity Investigation by an Acoustic Method

Drichko

Diakonov

Kagan

et al. 1998

phys. stat. sol. (b)

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The parameters of two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure were determined by an acoustical (contactless) method in the delocalized electrons region (B ≤2.5T).Nonlinear effects in Surface Acoustic Wave (SAW) absorption by 2DEG are determined by the electron heating in the electric field of SAW, which may be described in terms of electron temperature T e . The energy relaxation time τ ǫ is determined by the scattering at piezoelectric potential of acoustic phonons with strong screening. At different SAW frequencies the heating depends on the relationship between ωτ ǫ and 1 and is determined either by the instantaneously changing wave field (ωτ ǫ < 1), or by the average wave power (ωτ ǫ > 1). 72.50, 73.40.

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Oscillations in the acousto-electric proximity coupling to a 2D electron gas

Cited by 28 publications

References 11 publications

Electron localization in sound absorption oscillations in the quantum Hall effect regime

Electron localization in sound absorption oscillations in the quantum Hall effect regime

Elastic scattering and absorption of surface acoustic waves by a quantum dot

The Nonlinear Effects in 2DEG Conductivity Investigation by an Acoustic Method

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