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Tunnelling
Published in David K Ferry, Quantum Mechanics, 2001
Initially, at low voltage, the leading term on the right-hand side makes ΔE<0. Hence, no tunnelling can occur until the voltage reaches a threshold that depends upon the lesser of the two capacitors. For the case in which C1=C2=C, the requirement becomes Va>e/Ceq. Tunnelling is prohibited and no current flows below this threshold voltage. This region of Coulomb blockade is a direct result of the additional Coulomb energy which is required for an electron to tunnel through one of the capacitors.
Coulomb Effects in Short Coherent Conductors
Published in Andrei D. Zaikin, Dmitry S. Golubev, Dissipative Quantum Mechanics of Nanostructures, 2019
Andrei D. Zaikin, Dmitry S. Golubev
In Chapter 7, we have already analyzed charging effects in normal tunnel junctions characterized by small transmissions (Tn ≪ 1) of all their conducting channels. We demonstrated that at sufficiently low temperatures, electron–electron interactions tend to suppress electron transport across such junctions. This effect is usually called Coulomb blockade of electron tunneling. Assume now that instead of a tunnel barrier between two bulk metallic leads, one would place a short coherent conductor characterized by arbitrary transmission distribution of its conducting channels Tn, as described, e.g., in Section 10.1. Do Coulomb blockade effects persist also in this case? The answer to this question will be presented here.
History of Low-Power Electronics
Published in Christian Piguet, Low-Power CMOS Circuits, 2018
Quantum dots are based on the Coulomb blockade effect, and electrons are moved one by one from dot to dot. They have been constructed atom by atom by atomic force microscopes. Due to noise, it is better to construct cellular automata with several dots, and to define a given state of the automata as the logic “0” and another state as “1.” Majority gates have been demonstrated as well as AND/OR gates. The main problem is still how to interconnect these gates to provide useful functions. Furthermore, it is hard to construct a complete chip atom by atom with several billion elements.
Design of comb-shaped single-electron slime mold circuit and its application to traveling salesman problem
Published in International Journal of Parallel, Emergent and Distributed Systems, 2022
Because the amount of information exchanged in this Information Age increases yearly, highly efficient information processing devices are required to handle it. Nanotechnology has advanced, resulting in the development of nano-scaled devices (e.g. tunneling field effect transistors [1, 2], single-dopant devices [3], single molecule devices [4, 5], and other useful devices [6–9]). In this study, we focus on single-electron (SE) devices [10]. SE devices can control individual electrons by harnessing a quantum effect (Coulomb blockade effect [10]), and they have key advantages such as parallel processing [11] and stochastic operation. However, although many applications based on SE devices have been proposed [12–15], a suitable information processing method needs to be developed for the circuits of these devices.
Atom chips with free-standing two-dimensional electron gases: advantages and challenges
Published in Journal of Modern Optics, 2018
G. A. Sinuco-León, P. Krüger, T. M. Fromhold
Once the limiting factors to reduce the atom-surface distance are overcome, tiny currents in the chip can produce significant changes in the atom cloud’s density. This paves the way to developing more complex applications where solid-state devices are coupled to trapped atoms in their neighbourhood [33]. For example, single-electron transistors (SETs) may be switched by the presence/absence of an atom, excited atoms may couple to electrons in 2DEGs to modify their dynamics, and atomic Rydberg states may trigger Coulomb blockade in SETs.
Design of slime-mold-inspired multi-layered single-electron circuit
Published in International Journal of Parallel, Emergent and Distributed Systems, 2019
Recently, nano-scaled devices (i.e. single-molecule devices [1,2], tunneling field effect transistors [3,4], single-dopant devices [5], and so on [6–9]) have gained focus due to their unique properties and the design, construction, and fabrication of their unit elements is possible because of advances in nanotechnology. We focus on single-electron circuits (SECs) as the emerging nano-scaled devices, which consist mainly of tunnel junctions that can operate using individual electrons, have quantum effects (Coulomb blockade), etc. These circuits have many advantages, including extremely low power consumption, being highly integrated, and so on. Therefore, we have tried to design unique information processing systems using them [10–16]. Although many applications for SECs have been proposed up to now, the most appropriate information processing systems for the SECs have yet to be decided. As a candidate of the system, we draw inspiration from a natural phenomenon, i.e. behaviours shown in slime molds, that can be regarded as a form of information processing. Slime molds can feed efficiently by using the volatile chemical ‘cAMP’ that the slime molds generated themselves. When one cell of the slime molds feeds, it secretes cAMP and the other cells are attracted towards the higher cAMP concentration [17–20]. By repeating this cycle of finding food, secreting cAMP and attracting other cells towards the cAMP, they find an efficient route. It is reported that the feeding behaviours of slime molds enable them to solve mazes [21], form ringed networks like a real railway network [22], and so on [23–26]. Therefore, mimicking their behaviour is expected to provide a basis for a novel information-processing architecture [27–30]. In this paper, we propose a novel and unique SEC that mimics the behaviour of slime molds. We have tried to design some types of single-electron slime-mold circuits so far. The approach in this study is new. In concrete, in previous study described in Ref. [12], we focused on the slime mold model on cellular automata. This was the analog–digital mixed SEC. In contrast, in Ref. [14], we focused on original behaviour of the slime mold as a first trial. But we did not focus on the cAMP. The circuit structure is also different. Therefore, the differences of this study are the focused model and circuit design. We think the proposed approach should be suitable for the SECs to be constructed comparing with the previous works.