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Tunnel junction

About: Tunnel junction is a research topic. Over the lifetime, 6087 publications have been published within this topic receiving 118792 citations.


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Journal ArticleDOI
TL;DR: In this article, a formula for the electric tunnel effect through a potential barrier of arbitrary shape existing in a thin insulating film was derived for a rectangular barrier with and without image forces, where the true image potential was considered and compared to the approximate parabolic solution derived by Holm and Kirschstein.
Abstract: A formula is derived for the electric tunnel effect through a potential barrier of arbitrary shape existing in a thin insulating film. The formula is applied to a rectangular barrier with and without image forces. In the image force problem, the true image potential is considered and compared to the approximate parabolic solution derived by Holm and Kirschstein. The anomalies associated with Holm's expression for the intermediate voltage characteristic are resolved. The effect of the dielectric constant of the insulating film is discussed in detail, and it is shown that this constant affects the temperature dependence of the J‐V characteristic of a tunnel junction.

3,727 citations

Journal ArticleDOI
TL;DR: In this paper, the Bogoliubov equations were used to model the transmission and reflection of particles at the tunnel junction of normal-superconducting micro-constriction contacts, and a simple theory for the $I\ensuremath{-}V$ curves of normal superconducting contacts was proposed to describe the crossover from metallic to tunnel junction behavior.
Abstract: We propose a simple theory for the $I\ensuremath{-}V$ curves of normal-superconducting microconstriction contacts which describes the crossover from metallic to tunnel junction behavior. The detailed calculations are performed within a generalized semiconductor model, with the use of the Bogoliubov equations to treat the transmission and reflection of particles at the $N\ensuremath{-}S$ interface. By including a barrier of arbitrary strength at the interface, we have computed a family of $I\ensuremath{-}V$ curves ranging from the tunnel junction to the metallic limit. Excess current, generated by Andreev reflection, is found to vary smoothly from $\frac{4\ensuremath{\Delta}}{3e{R}_{N}}$ in the metallic case to zero for the tunnel junction. Charge-imbalance generation, previously calculated only for tunnel barriers, has been recalculated for an arbitrary barrier strength, and detailed insight into the conversion of normal current to supercurrent at the interface is obtained. We emphasize that the calculated differential conductance offers a particularly direct experimental test of the predictions of the model.

2,772 citations

Journal ArticleDOI
22 Mar 1996-Science
TL;DR: In this paper, the authors inserted conjugated molecules, which were 4,4′-di(phenylene-ethynylene)benzenethiolate derivatives, formed single molecular wires that extended from the Au{111} substrate to about 7 angstroms above.
Abstract: Molecular wire candidates inserted into “nonconducting” n -dodecanethiol self-assembled monolayers on Au{111} were probed by scanning tunneling microscopy (STM) and microwave frequency alternating current STM at high tunnel junction impedance (100 gigohms) to assess their electrical properties. The inserted conjugated molecules, which were 4,4′-di(phenylene-ethynylene)benzenethiolate derivatives, formed single molecular wires that extended from the Au{111} substrate to about 7 angstroms above and had very high conductivity as compared with that of the alkanethiolate.

1,094 citations

Journal ArticleDOI
TL;DR: In this article, the authors adapt the spin accumulation model of the perpendicular transport in metallic magnetic multilayers to the issue of spin injection from a ferromagnetic metal (F) into a semiconductor (N) by introducing a spin dependent interface resistance (tunnel junction preferably) at the $F/N$ interfaces.
Abstract: We adapt the spin accumulation model of the perpendicular transport in metallic magnetic multilayers to the issue of spin injection from a ferromagnetic metal (F) into a semiconductor (N). We show that the problem of the conductivity mismatch between F and N can be solved by introducing a spin dependent interface resistance (tunnel junction preferably) at the $F/N$ interfaces. In the case of a $F/N/F$ structure, a significant value of the magnetoresistance can be obtained if the junction resistance at the $F/N$ and $N/F$ interfaces is chosen between two threshold values depending on the resistivity, spin diffusion length and thickness of N. The problem is treated for various geometries (vertical or lateral $F/N/F$ structures).

975 citations

Journal ArticleDOI
Ping Sheng1
TL;DR: In this article, it is shown that the electrical conduction can be attributed to a novel mechanism, fluctuation-induced tunneling, in which the thermally activated voltage fluctuations across insulating gaps play an important role in determining the temperature and field dependences of the conductivity.
Abstract: In disordered materials generally characterized by large conducting regions (or long conducting pathways) separated by small insulating barriers, it is shown that the electrical conduction can be ascribed to a novel mechanism, fluctuation-induced tunneling, in which the thermally activated voltage fluctuations across insulating gaps play an important role in determining the temperature and field dependences of the conductivity. By considering the modulating effects induced by voltage fluctuations on either an image-force corrected rectangular potential barrier or a parabolic barrier, a theoretical expression for the tunneling conductivity is derived which displays thermally activated characteristics at high temperatures but becomes identical to the temperature-independent simple elastic tunneling at low temperatures. Between the two limiting behaviors the temperature dependence of the conductivity is controlled by the shape of the tunneling barrier. An expression for the high-field tunneling current is similarly obtained. It is found that, while the tunneling current increases as a nonlinear function of the field, the degree of nonlinearity decreases as the temperature increases, indicating an effective lowering and narrowing of the barrier by voltage fluctuations. The theory is also generalized from the consideration of a single tunnel junction to a random network of tunnel junctions by the application of the effective-medium theory. The theoretical predictions are compared with the experimental results for three disordered systems: (1) carbon-polyvinylchloride composites, (2) heavily doped, closely compensated GaAs, and (3) doped polyacetylene ${(\mathrm{CH})}_{x}$ in the metallic regime. In each case excellent agreement is obtained. It is shown in particular that the nonmetallic temperature dependence of the resistivity in doped metallic ${(\mathrm{CH})}_{x}$ samples can be understood in terms of the present theory.

898 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202325
202250
2021100
2020174
2019173
2018168