Effect of spatial dispersion on acoustoelectric current in a high-mobility two-dimensional electron gas

Shilton, J. M.; Mace, D. R.; Talyanskii, V. I.; Pepper, M.; Simmons, M. Y.; Churchill, A. C.; Ritchie, D. A.

doi:10.1103/physrevb.51.14770

Cited by 55 publications

(45 citation statements)

References 2 publications

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“…In particular, very interesting experimental studies of these effects in the quantum Hall regime were carried out in the works 1,4 . The second class of studies deals with the so-called acoustoelectric effect, namely a drag of 2D electrons by a traveling SAW [5][6][7][8][9] . This effect is due to a transfer of momentum from the SAW to the electrons due to SAWelectron interaction.…”

Section: Introductionmentioning

confidence: 99%

Giant oscillations of the acoustoelectric current in a quantum channel

Totland

Galperin

1997

Phys. Scr.

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A theory of d.c. electric current induced in a quantum channel by a propagating surface acoustic wave (acoustoelectric current) is worked out. The first observation of the acoustoelectric current in such a situation was reported by J. M. Shilton et al., Journ. Phys. C (to be published). The authors observed a very specific behavior of the acoustoelectric current in a quasi-one-dimensional channel defined in a GaAs-AlGaAs heterostructure by a split-gate depletion -giant oscillations as a function of the gate voltage. Such a behavior was qualitatively explained by an interplay between the energy-momentum conservation law for the electrons in the upper transverse mode with a finite temperature splitting of the Fermi level. In the present paper, a more detailed theory is developed, and important limiting cases are considered.

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Section: Introductionmentioning

confidence: 99%

Giant oscillations of the acoustoelectric current in a quantum channel

Totland

Galperin

1997

Phys. Scr.

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“…One class of effects is induced magneto-oscillations that originate from the geometric commensurability between the cyclotron radius R c and the period 2π/q of spatially periodic perturbations [10], which has been observed in statically modulated 2D systems [11,12,13]. This effect was recently studied in the attenuation and renormalization of surface acoustic wave (SAW) velocity due to interactions with electrons [9,14] and in the drag effect [14]. For a spatially periodic propagating field of the SAW, the commensurability effect can also be viewed as the resonant SAW interaction with collective excitations of 2D electrons at finite wavenumbers [9,15], enabling one to excite modes otherwise forbidden by Kohn's theorem [16].…”

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confidence: 99%

Surface Acoustic-Wave-Induced Magnetoresistance Oscillations in a Two-Dimensional Electron Gas

et al. 2004

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We study the geometrical commensurability oscillations imposed onto the resistivity of 2D electrons in a perpendicular magnetic field by a propagating surface acoustic wave (SAW). We show that, for ω < ωc, this effect is composed of an anisotropic dynamical classical contribution increasing the resistivity and the non-equilibrium quantum contribution isotropically decreasing resistivity, and we predict the appearance of zero-resistance states associated with geometrical commensurability at large SAW amplitude. We also describe how the commensurability oscillations modulate the resonances in the SAW-induced resistivity at multiples of the cyclotron frequency.High-mobility two-dimensional electron gases (2DEGs) display interesting effects under intense microwave irradiation [1,2,3,4,5,6,7] or the influence of surface acoustic waves in the microwave frequency range [8,9]. One class of effects is induced magneto-oscillations that originate from the geometric commensurability between the cyclotron radius R c and the period 2π/q of spatially periodic perturbations [10], which has been observed in statically modulated 2D systems [11,12,13]. This effect was recently studied in the attenuation and renormalization of surface acoustic wave (SAW) velocity due to interactions with electrons [9,14] and in the drag effect [14]. For a spatially periodic propagating field of the SAW, the commensurability effect can also be viewed as the resonant SAW interaction with collective excitations of 2D electrons at finite wavenumbers [9,15], enabling one to excite modes otherwise forbidden by Kohn's theorem [16].In this Letter, we study the non-linear dynamical effect in which SAWs induce changes in the magneto-resistivity of a high quality electron gas in the regime of classically strong magnetic fields, ω c τ ≫ 1 and high temperatures k B T ≫ ω c . We show that the resistivity changes reflect both frequency and geometrical resonances in the surface acoustic wave attenuation and are formed from two competing contributions.The first contribution originates from the SAWinduced guiding center drift of the cyclotron orbits -a purely classical effect. For a SAW with frequency ω, and wavenumber q, propagating in the x direction with speed s = ω/q, there is an anisotropic increase in the resistivity ρ xx (at high fields ω c τ ≫ 1, this is equivalent to an increase of conductivity in the transverse direction σ yy ), which oscillates as a function of inverse magnetic field when the Fermi velocity v F ≫ s. We show that at ω ω c the resistivity change displays resonances at multiples of the cyclotron frequency ω ≈ N ω c .The second contribution arises from the modulation of the electron density of states (DOS),γ(ǫ) = [1 − Γ cos (2πǫ/ ω c )] γ (where γ = m/π 2 ), and consequently, from the energy dependence of the nonequilibrium population of excited electron states caused by Landau level quantization. We follow the idea proposed in Ref.[6] to explain the formation of zeroresistance states [1, 2, 4] under microwave irradiation with ω ω c . We show...

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“…That is, the nature of the oscillations for the acoustoelectric current is the same as that of that of the well-known Weiss oscillations which were observed for the magnetoresistivity of a modulated 2DEG [7,8]. Commensurability oscillations of a non-quantized acoustoelectric current were reported in [9]. Admittedly, a systematic theoretical study of the geometrical oscillations of the quantized acoustoelectric current is a very complicated problem and cannot be solved analytically.…”

Section: Introductionmentioning

confidence: 67%

“…Therefore, in our calculations we may assume that the quantum oscillations are smeared out, and we can identify the energy of the highest Landau level with the Fermi energy E F in the absence of the external magnetic field. The second term in the expression (9) gives rise to the well-known Weiss oscillations in the magnetoresistance of a modulated 2DEG [7,8,10,11,12]. The amplitude of these commensurability oscillations also depends on temperature.…”

Section: The Model and Numerical Resultsmentioning

confidence: 99%

The effect of a magnetic field on the acoustoelectric current in a narrow channel

Zimbovskaya¹,

Gumbs²

2001

J. Phys.: Condens. Matter

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The effect of a perpendicular magnetic field on the quantized current induced by a surface acoustic wave in a quasi-1D channel is studied. The channel has been produced experimentally in a GaAs heterostructure by shallow etching techniques and by the application of a negative gate voltage to Schottky split gates. Commensurability oscillations of the quantized current in this constriction have been observed in the interval of current between quantized plateaus. The results can be understood in terms of a moving quantum dot with the electron in the dot tunneling into the adjacent twodimensional region. The goal is to explain qualitatively the mechanism for the steplike nature of the acoustoelectric current as a function of gate voltage and the oscillations when a magnetic field is applied. A transfer Hamiltonian formalism is employed.

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Effect of spatial dispersion on acoustoelectric current in a high-mobility two-dimensional electron gas

Cited by 55 publications

References 2 publications

Giant oscillations of the acoustoelectric current in a quantum channel

Giant oscillations of the acoustoelectric current in a quantum channel

Surface Acoustic-Wave-Induced Magnetoresistance Oscillations in a Two-Dimensional Electron Gas

The effect of a magnetic field on the acoustoelectric current in a narrow channel

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