Experimental study of the acoustoelectric effects in GaAs-AlGaAs heterostructures

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

doi:10.1088/0953-8984/7/39/010

Cited by 37 publications

(37 citation statements)

References 16 publications

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“…Both classes of effects have been intensely studied over the years. [1][2][3][4][5][6][7][8][9] Recently, the SAW-induced acoustoelectic current was measured in quasi-one-dimensional ballistic electron channel defined in a GaAs/Al x Ga 1Ϫx As heterostructure by split gates. [11][12][13] At various SAW power levels, the experiments in Refs.…”

Section: Introductionmentioning

confidence: 99%

Screening of the surface-acoustic-wave potential by a metal gate and the quantization of the acoustoelectric current in a narrow channel

1998

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The piezoelectric potential accompanying a surface acoustic wave ͑SAW͒ launched on the surface of a GaAs/Al x Ga 1Ϫx As heterostructure is calculated. The screening due to a narrow metal gate on the surface is included and a closed form analytic solution for the SAW potential is obtained. This potential is used to calculate the SAW-induced acoustoelectric current in a quasi-one-dimensional electron channel formed in the heterostructure by the split gates. At gate voltages beyond the pinch off, electrons are transported through the channel in local quantum wells formed by the SAW potential. In recent experiments, Talyanskii et al. ͓Phys. Rev. B 56, 15 180 ͑1997͔͒ found that, in this regime, the acoustoelectric current I versus the gate voltage displays a step-like behavior. The values of the current on the plateaus are quantized with Iϭne f where e is electron charge, f is the SAW frequency, and n is the number of electrons transported through the channel per SAW cycle. Using a simple model for the electrostatic barrier in the channel, we show that when one electron is trapped in the quantum well, the current depends on a parameter ␤ defined as the ratio of the piezoelectric potential amplitude to the height of the electrostatic barrier. When ␤ increases, the current rapidly increases from zero to its quantized value Iϭe f . The obtained results explain the first current plateau and qualitatively agree very well with the experiment. ͓S0163-1829͑98͒00540-2͔

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Section: Introductionmentioning

confidence: 99%

Screening of the surface-acoustic-wave potential by a metal gate and the quantization of the acoustoelectric current in a narrow channel

1998

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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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“…Recently, there has been considerable interest in the low temperature measurement of the attenuation and phase shift of a SAW caused by a two-dimensional electron system in the Al x Ga 1−x As/GaAs heterostructure or in the structure of a GaAs film on a LiNbO 3 substrate [11]- [13]. The governing equations for this study are essentially the same as given here.…”

Section: A Infinitesimally Thin Semiconductormentioning

confidence: 99%

Acousto-electric attenuation in a layered structure analyzed by the transmission line technique

Wang¹,

Lin²

1999

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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In general, theoretical determination of attenuation of ultrasonic waves caused by acousto-electric interaction in any structure is cumbersome and difficult. However, by adopting a transmission line model and using the technique of capacitance perturbation, the analytical process can be greatly simplified. In this paper, we start to analyze a simple structure of an infinitesimally thin semiconductor film deposited on a SAW substrate without an isolation layer in-between. Results for a simplified case are obtained. This analysis is then extended to the general layer structure for both an arbitrary thickness semiconductor layer and an isolation layer. The device parameters are chosen such that the charge relaxation time is much smaller than the duration of the wavelength. Therefore, the electric potential accompanying the acoustic wave is thoroughly screened. Thus, the induced electric field beyond a Debye length or at the top of the semiconductor is negligible. Under this condition, the induced potential as well as the space charge density waves possess a simple form. By integrating the space charge across the thickness of the semiconductor, an effective surface charge density is obtained. With the surface charge density known, one can readily calculate the value of the perturbed capacitance and determine the attenuation constant. The results are in agreement with other analyses.

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Experimental study of the acoustoelectric effects in GaAs-AlGaAs heterostructures

Cited by 37 publications

References 16 publications

Screening of the surface-acoustic-wave potential by a metal gate and the quantization of the acoustoelectric current in a narrow channel

Screening of the surface-acoustic-wave potential by a metal gate and the quantization of the acoustoelectric current in a narrow channel

Giant oscillations of the acoustoelectric current in a quantum channel

Acousto-electric attenuation in a layered structure analyzed by the transmission line technique

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