Scanning-tunneling-microscope observations of Coulomb blockade and oxide polarization in small metal droplets

Wilkins, R.; Ben‐Jacob, Eshel; Jaklevic, R. C.

doi:10.1103/physrevlett.63.801

Cited by 223 publications

(91 citation statements)

References 19 publications

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“…Such modulation has been observed in several experiments. [3][4][5][6][7] Existing "orthodox" theory of correlated single electron tunneling 1'2 assumes that the energy spectra of the junction electrodes are continuous, an assumption that is valid for not too small particles (~>10 nm or so). The energy spectra of the smaller electrodes are discrete due to the quantum-size effect.…”

Section: Introductionmentioning

confidence: 99%

Correlated single-electron tunneling via mesoscopic metal particles: Effects of the energy quantization

Averin

Korotkov

1990

J Low Temp Phys

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The existing theory of correlated single-electron tunneling in the double normalmetal tunnel junction is extended to the case of an ultrasmall central electrode of the structure. It is shown that the form of the I-V curve of such a system depends on the energy relaxation rate in this electrode. For realistic values of the relaxation rate, the large-scale shape of the dc I-V curve, which is associated with Coulomb correlations, is close to that following from the earlier theory.However, the I-V curve should also exhibit small-scale singularities reflecting the structure of the energy spectrum of the central electrode.

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Section: Introductionmentioning

confidence: 99%

Correlated single-electron tunneling via mesoscopic metal particles: Effects of the energy quantization

Averin

Korotkov

1990

J Low Temp Phys

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“…The tunneling current jumps when the maximum charge changes. Recently, the CS has been observed by using a tip of scanning tunneling microscope(STM) of nanometer-size in highly resistive granular films [2-5] as well as metaldroplet systems [6,7]. For a granular film, which is considered to be an array of tunnel junctions, the observed CS implies that a bottleneck exists in the conducting paths.…”

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confidence: 99%

Coulomb staircase in STM current through granular films

et al. 2000

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The electron transport through an array of tunnel junctions consisting of an STM tip and a granular film is studied both theoretically and experimentally. When the tunnel resistance between the tip and a granule on the surface is much larger than those between granules, a bottleneck of the tunneling current is created in the array. It is shown that the period of the Coulomb staircase(CS) is given by the capacitance at the bottleneck. Our STM experiments on Co-Al-O granular films show the CS with a single period at room temperature. This provides a new possibility for single-electron-spinelectronic devices at room temperature.Charging effects on single electron tunneling such as Coulomb blockade and Coulomb oscillation have attracted much interest [1]. Recent advances in nanotechnology enable us to fabricate small tunnel junctions where charging effects play an essential role. The I-V characteristics for double tunnel junction systems have been extensively studied, where the step-like structure called Coulomb staircase(CS) is observed when the resistances between the junctions are not equal [1]. For these asymmetric double junction systems, the junction with a large resistance behaves like a bottleneck of the tunneling current and the central island is charged through the other junction up to the maximum charge. The tunneling current jumps when the maximum charge changes. Recently, the CS has been observed by using a tip of scanning tunneling microscope(STM) of nanometer-size in highly resistive granular films [2-5] as well as metaldroplet systems [6,7]. For a granular film, which is considered to be an array of tunnel junctions, the observed CS implies that a bottleneck exists in the conducting paths. However, the physics behind the CS in a granular film is not clear because it contains many granules with different size and the conducting path may form a three-dimensional network in a thick granular film.Bar-Sadeh et al. have studied the STM current through a nonmagnetic granular film, Au-Al 2 O 3 , by using the cryogenic STM [2,3]. They observed the CS at temperatures T = 4.2 and 78 K, and analyzed the experimental data by using a triple barrier model. They assumed that the rate for tunneling between two granules is small and the number of excess electrons in each granule is treated independently. Because of these assumptions, the CS was given by the superposition of two different periods in their model: one was determined by the tunnel process between the STM tip and a granule, the other between another granule and the base electrode. On the contrary, as we will show later, the CS has a single period which is determined by the capacitance at the bottleneck.In this Letter, we study the electron transport through an array of tunnel junctions consisting of an STM tip and a granular film both theoretically and experimentally. In this system, we can vary the tunnel resistance between the tip and a granule on the surface by changing the distance between them. When the tunnel resistance between the tip and a granule ...

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“…[3][4][5][6] The tip then acts as one of the leads to a small metallic grain, which is situated on a thin insulating layer on top of a conducting substrate ͑this is the other lead͒. If the capacitance of the grain to its environment is sufficiently small, the charging energy dominates the electron transport.…”

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Semiconductor band switching by charging a small grain with a single electron

et al. 1996

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We observe a very abrupt change in the electron density in scanning tunneling microscope measurements on an InAs͑110͒ surface in the vicinity of a small conductive grain. The observed features are a consequence of charge quantization on the grain, which acts as a single-electron gate electrode. The band bending at the surface changes stepwise when an extra electron is added to the grain, resulting in a sharp closed curve around the grain in topographic images. Features due to the screening of the residual charge of the grain are also discussed.

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Scanning-tunneling-microscope observations of Coulomb blockade and oxide polarization in small metal droplets

Cited by 223 publications

References 19 publications

Correlated single-electron tunneling via mesoscopic metal particles: Effects of the energy quantization

Correlated single-electron tunneling via mesoscopic metal particles: Effects of the energy quantization

Coulomb staircase in STM current through granular films

Semiconductor band switching by charging a small grain with a single electron

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