Giant acoustoelectric current in suspended quantum point contacts

Kreft, Dustin J.; Mourokh, Lev G.; Shin, Hyun Cheol; Bichler, Max; Wegscheider, Werner; Blick, Robert H.

doi:10.1103/physrevb.94.235305

Cited by 7 publications

(6 citation statements)

References 20 publications

(24 reference statements)

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“…[231][232][233] Subsequently, the Rayleigh SAW, viewed as a moving electrical superlattice potential, was shown to modify the electronic dispersion of ballistic graphene close to the charge-neutrality point [234][235][236] with an acoustoelectric current that is dependent on the SAW propagation direction. [237][238][239] Similar acoustoelectric coupling has also been observed in graphene ranoribbons, [240,241] QDs, [242][243][244][245] suspended quantum point contacts, [246] GaAs [247] and GaAs/AlGaAs hetrostructures, [248,249] and, more recently, 2D materials such as MoS 2 [250] and black phosphorous, [251] in which an anomalous acoustoelectric current was sustained.…”

Section: Electronic Manipulationmentioning

confidence: 75%

High Frequency Sonoprocessing: A New Field of Cavitation‐Free Acoustic Materials Synthesis, Processing, and Manipulation

et al. 2020

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Ultrasound constitutes a powerful means for materials processing. Similarly, a new field has emerged demonstrating the possibility for harnessing sound energy sources at considerably higher frequencies (10 MHz to 1 GHz) compared to conventional ultrasound (⩽3 MHz) for synthesizing and manipulating a variety of bulk, nanoscale, and biological materials. At these frequencies and the typical acoustic intensities employed, cavitation-which underpins most sonochemical or, more broadly, ultrasound-mediated processes-is largely absent, suggesting that altogether fundamentally different mechanisms are at play. Examples include the crystallization of novel morphologies or highly oriented structures; exfoliation of 2D quantum dots and nanosheets; polymer nanoparticle synthesis and encapsulation; and the possibility for manipulating the bandgap of 2D semiconducting materials or the lipid structure that makes up the cell membrane, the latter resulting in the ability to enhance intracellular molecular uptake. These fascinating examples reveal how the highly nonlinear electromechanical coupling associated with such high-frequency surface vibration gives rise to a variety of static and dynamic charge generation and transfer effects, in addition to molecular ordering, polarization, and assembly-remarkably, given the vast dimensional separation between the acoustic wavelength and characteristic molecular length scales, or between the MHz-order excitation frequencies and typical THz-order molecular vibration frequencies.

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Section: Electronic Manipulationmentioning

confidence: 75%

High Frequency Sonoprocessing: A New Field of Cavitation‐Free Acoustic Materials Synthesis, Processing, and Manipulation

et al. 2020

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“…Most of the studied low-dimensional electron systems are based on a two-dimensional electron gas (2DEG) embedded in a semiconductor bulk, such as, for example, in a GaAs/ AlGaAs heterostructure. However, this widely used material is also suitable for creating low-dimensional electron systems in thin heterostructural membranes freely suspended over a substrate [1][2][3][4][5][6][7][8][9]. To achieve this, at the growth stage, a sacrificial layer with a high aluminum content is incorporated into the heterostructure between the substrate and the overlying layers which subsequently form a membrane.…”

Section: Introductionmentioning

confidence: 99%

The piezoelectric gating effect in a thin bent membrane with a two-dimensional electron gas

Shevyrin

Pogosov

2018

J. Phys.: Condens. Matter

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Thin suspended nanostructures with a two-dimensional electron gas can be used as nanoelectromechanical systems in which electron transport is piezoelectrically coupled to mechanical motion and vibrations. Apart from practical applications, these systems are interesting for studying electron transport under unusual conditions, namely, in the presence of additional mechanical degrees of freedom. In the present paper, we analyze the influence of the bending on the density of a gated two-dimensional electron gas contained in a suspended membrane using the Thomas-Fermi approach and the model of pure electrostatic screening. We show that a small bending is analogous to a small change in gate voltages. Our calculations demonstrate that the density change is most prominent near the edges of the conductive channel created by negatively biased gates. When moving away from these edges, the bending-induced density change rapidly decays. We propose several methods to increase the magnitude of the effect, with the largest benefit obtained from coverage of the conductive channel with an additional grounded gate. It is shown that, for a conductive channel under a bare surface, the largest effect can be achieved if the two-dimensional electron gas is placed near the middle of the membrane thickness, despite the bending-induced strain is zero there.

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“…The negative current and the current oscillations at even larger negative gate voltages are related to different physical mechanisms as addressed in Ref. 6.…”

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confidence: 96%

“…where the dependence of the conductivity on the gate voltage, r exp (V g ), can be taken from the experimental data of Ref. 6. The effect of the magnetic field is given by 10…”

mentioning

confidence: 99%

Effects of electron confinement on the acoustoelectric current in suspended quantum point contacts

Mourokh

Ivanushkin

Kreft

et al. 2017

Applied Physics Letters

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An acoustoelectric current driven through a quantum point contact (QPC) on a suspended nanobridge by surface acoustic waves displays a non-trivial behavior in the presence of a perpendicular magnetic field. Our study reveals that the dependencies of this current on the QPC gate voltage and magnetic field can be explained by a variable material parameter r m. We develop a theoretical model for this phenomenon based on the modification of the Coulomb interaction and, correspondingly, the electron-SAWs coupling in the presence of the electron confinement.

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Giant acoustoelectric current in suspended quantum point contacts

Cited by 7 publications

References 20 publications

High Frequency Sonoprocessing: A New Field of Cavitation‐Free Acoustic Materials Synthesis, Processing, and Manipulation

High Frequency Sonoprocessing: A New Field of Cavitation‐Free Acoustic Materials Synthesis, Processing, and Manipulation

The piezoelectric gating effect in a thin bent membrane with a two-dimensional electron gas

Effects of electron confinement on the acoustoelectric current in suspended quantum point contacts

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