Intrinsic bistability in nonlinear transport through a submicron lateral barrier

Pilling, G.; Cobden, David; McEuen, Paul L.; Duruöz, C. I.; Harris, James S.

doi:10.1016/0039-6028(96)00492-x

Cited by 7 publications

(13 citation statements)

References 6 publications

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“…Interestingly, an apparently similar sudden onset of source-drain current in the I-V characteristic was observed in the tunneling across a submicron trench in a 2DES at zero magnetic field. 10 However, the similarities concern only the appearance of the effect, as the experiments by Pilling et al were explained by a sudden onset of charge transfer via a deeper 2D layer due to field emission under a permanent illumination. 10 In our case, the onset of current flow near the constriction of the Corbino samples is due to the nonequilibrium population of higher Landau levels.…”

Section: Methodsmentioning

confidence: 99%

Tunneling between edge states in the quantum Hall regime limited by a mesoscopic island: A current-plateau phenomenon

Liu¹,

Nachtwei²,

Groß³

et al. 1998

Phys. Rev. B

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Well-developed current plateaus have been observed in the I-V characteristics of Corbino devices in the quantum Hall regime, if a striplike island of mesoscopic dimensions is located between two trench fingers which are etched radially between the central and outer Ohmic contacts. The trenches are 100 nm wide and define, together with the island, two constrictions of 550-700-nm width. The current plateaus are due to a limitation of the tunneling rate by the filling of nonequilibrium states around the island. The evolution of the current plateaus with the filling factor is qualitatively explained by quasielastic inter-Landau-level tunneling. The latter mechanism determines the onset of the tunneling-current plateau, which extends until the complete local breakdown of the quantum Hall regime around the island is reached. We investigated this tunneling phenomenon as a function of the temperature in the range from 23 mK to 2.1 K, and for various sizes of the island, ranging from 100ϫ250 nm 2 to 100 nmϫ8 m. The plateaus were better pronounced, the lower the temperature and the smaller the island was. To explain the observed tunneling-current plateaus, we suggest a picture including the properties of the edge states ͑near the trenches and around the island͒ and the incompressible quantum Hall region in between them.

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Section: Methodsmentioning

confidence: 99%

Tunneling between edge states in the quantum Hall regime limited by a mesoscopic island: A current-plateau phenomenon

Liu¹,

Nachtwei²,

Groß³

et al. 1998

Phys. Rev. B

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“…It is known, however, that illumination with an LED at low temperatures also flattens the bands in the GaAs by neutralizing acceptors deep in the substrate [2]. Indeed, we have previously seen very similar behaviour in etched barriers on standard heterostructures with no back gate, but only after illumination with red light at 4.2 K [4], and we have subsequently found that a voltage applied to the chip carrier has much the same effect on the characteristics as has V g in the present devices. These standard heterostructures too have an upside-down heterojunction around 1µm below the normal one, at the top of the superlattice buffer.…”

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confidence: 53%

“…Second, they illustrate the existence of a thermal instability in an initially insulating, low-density 2DEG. Finally, they offer insight into a number of recent experiments on transport across a lateral barrier [4,5,6,7] on a GaAs/AlGaAs heterostructure. The latter experiments all revealed very similar behaviour to that reported here.…”

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confidence: 99%

Current flow past an etched barrier: field emission from a two-dimensional electron gas

et al. 1998

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PACS. 73.40Kp -III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions. PACS. 79.70.+q -Field emission, ionization, evaporation, and desorption.Abstract. -We find that, under appropriate conditions, electrons can pass a barrier etched across a two dimensional electron gas (2DEG) by field emission from the GaAs/AlGaAs heterojunction into a second, low-density 2DEG formed deep in the substrate. The current-voltage characteristics exhibit a rapid increase in the current at the field emission threshold and intrinsic bistability above this threshold, consistent with a heating instability occurring in the second 2DEG. These results may explain similar behaviour recently seen in a number of front-gated devices by several groups.Extensive studies of two-dimensional electron systems over the last two decades have relied on the ability to trap electrons at an interface between two materials with different band energies. Most popular amongst these systems is the high-mobility GaAs/Al x Ga 1−x As heterojunction [1]. Here the electrons are confined principally by attraction to remote donors placed in the AlGaAs. However, in order for there to be complete confinement there must also exist an electric field in the GaAs substrate pushing the electrons towards the heterojunction. In practice, this substrate field is typically provided by negative charge on residual acceptors in the substrate and surface boundary conditions [2]. A very interesting situation arises if this confinement field vanishes. The electrons are then predicted to be very weakly bound at the interface, by the work function of the 2DEG, as discussed by Groshev and Schoen [3]. The work function depends sensitively on the density of the 2DEG and is strongly influenced by many-body effects such as the image potential. Because of the weak confinement, field emission of electrons into the substrate may be anticipated in a weak electric field applied perpendicular to the interface.In this letter we discuss a simple device that demonstrates the field emission of electrons from a 2DEG. We find that a current can flow past an etched barrier in a 2DEG if the Typeset using EURO-T E X

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“…The SPI resembles the imaginary time path integral for the evolution operator of a quantum particle with coordinate Q and momentum λ, but the canonical "Hamiltonian" H given by (7) is not Hermitian. Nevertheless, we can apply the Hamiltonian formalism to our path integral (6). A large parameter, the number of elementary charges participating in the transport, allows the saddle-point evaluation of the SPI (6) leading to the canonical equations of motioṅ…”

Section: The Modelmentioning

confidence: 99%

“…4,5 Bistable fluctuations have been observed in microstructures by many different experimental groups. [6][7][8][9][10] In these experiments, the switching is usually induced by thermal fluctuations, not the non-equilibrium ones we are principally concerned with here. The thermal mechanism can be identified because the switching rates were found to be well fit by an exponential of the applied bias, consistent with Boltzmann activation.…”

Section: Introductionmentioning

confidence: 99%

Transport statistics in bistable systems: a stochastic path integral approach (Invited Paper)

Jordan¹,

Sukhorukov²

2005

SPIE Proceedings

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We consider the non-equilibrium noise properties of bistable systems. The stochastic path integral formalism is derived and used to investigate the dynamics and distribution of transmitted charge. Microscopic fluctuations induce transitions between the two stable states, with rates found from an instanton calculation. On a long time scale, the system exhibits a random telegraph signal between the currents produced by the two stable states. We predict a universal ellipse law for the log-distribution of transmitted charge in the bistable current range, which applies to any type of bistable system, regardless of its origin.

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Intrinsic bistability in nonlinear transport through a submicron lateral barrier

Cited by 7 publications

References 6 publications

Tunneling between edge states in the quantum Hall regime limited by a mesoscopic island: A current-plateau phenomenon

Tunneling between edge states in the quantum Hall regime limited by a mesoscopic island: A current-plateau phenomenon

Current flow past an etched barrier: field emission from a two-dimensional electron gas

Transport statistics in bistable systems: a stochastic path integral approach (Invited Paper)

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