Solid State Physics is the largest branch of Condensed Matter Sciences. Makes sense that Solid State Atomic and Nuclear Physics nests within these arts of science.
Considering the semiconductor industry is exploring every possible combination of elements and molecules... In extremely well funded and equipped labs... One can expect important parallel, seemingly unrelated research, will lead to observations and discoveries of value to each.
Condensed Matter Nuclear Science and Solid State research will likely discover things that even make high energy fusion easier. I think Team Google might agree...
This recent paper describes nano and femto scale dendritic growth, controllable and switchable. Amazing!
I imagine similar phenomenon might increase output in LEC type devices and perhaps other types of LANR LENR energy technologies.
Advances in Solid State Ionics.... Sounds familiar?
"Atomic Scale Switches Based on Solid State Ionics"
Kazuya Terabe,Takashi Tsuchiya &Tohru Tsuruoka
Article, Accepted 06 Apr 2022, Published online: 13 Apr 2022
To cite this article:
Kazuya Terabe, Takashi Tsuchiya & Tohru Tsuruoka (2022) Atomic scale switches based on solid state ionics, Advances in Physics: X, 7:1, DOI: 10.1080/23746149.2022.2065217
ABSTRACT
The atomic scale switch, which operates on the principle of solid-state ionics, is an ultrafine device that takes advantage of the fact that the properties of materials can be changed significantly by the transport and chemical reaction of a small number of ions in a solid. The switch (e.g. ‘atomic switch’) actually works by using an ion-conducting solid electrolyte or an ion-/electron-conducting mixed-conductor as the device material, and by applying an external voltage to control local ion transport and electrochemical reaction. With the application of an external voltage, a bridge is formed as a conductive filament in the solid electrolyte or the mixed conductor between electrodes. The atomic structure of the point contact in said filament can be reversibly changed by precise control of the applied voltage. By controlling the atomic structure of the point contact, interesting functions are obtained, such as fast on/off resistive switching, switching between each state of quantized conductance and neuromorphic properties. This atomic scale switch has the potential to overcome the functional and performance limitations of conventional integrated circuits because it can be used in conjunction with extant semiconductor devices.
Introduction
Most information and communication equipment uses electronic components, such as a field-effect transistors, which operate using the characteristics of semiconductor materials, and the progress of such equipment is highly dependent on the performance of those semiconductor devices. There has been remarkable progress in improving the performance of semiconductor devices, which progress has been supported by technological developments in miniaturization and high-level integration, but there are concerns that this progress is beginning to wane. Therefore, in order for information and communication equipment to continue to improve and to help to develop the next generation advanced information society, it is expected that other high-performance devices, which operate on new principles, will be developed.
An atomic switch has been developed by Terabe et al., described herein, which is an atomic scale device that operates on new principles using ion transport [1–6]. Computers, which are the main information and communications equipment used, are collections of huge numbers of switches. Up until now, switching operations have been achieved by controlling electron transport using the properties of the individual semiconductors. In the atomic switch, however, the switching operation is performed by controlling ion transport and the electrochemical reactions that take place in the solid employed. Since this operation follows the principle of solid state ionics [7–9], atomic switches can be collectively referred to as solid-state ionic devices. Because the atomic switch works by transporting ions that are only a few nanometers in size, or are even at the atomic scale, it has the potential to surpass the switching function and performance of conventional semiconductor devices, even though it uses ions that are larger and heavier than electrons [10–12]. In addition, the miniaturization of devices in current information and communication equipment has reached a stage where it has become technically important to discuss their development on the atomic scale. The quantum behavior of materials with ultrafine structures may provide the basis for new device development, and atomic scale solid state ionic devices such as the atomic switch are excellent candidates for exploring superior functionality and performance.
Eigler et al. carried out a switching operation by controlling the transport of a single atom, and referred to their switch as an atomic switch [13]. They used a scanning tunneling microscope (STM) to control the transport of a single xenon atom between the substrate surface and the STM tip, in an ultra-high vacuum environment at a cryogenic temperature of 4 K. They found that depending on the position of the xenon atom, i.e. on the tip or on the substrate side, the electrical resistance (tunneling resistance) between the substrate and the STM tip changed by a factor of about seven. The transport of the xenon atom was reversible, the control of which was achieved by applying a voltage of appropriate polarity and magnitude between the substrate and the tip. Later, another atomic scale switch was reported by Smith et al. [14], who realized a switch operation using an atomic scale structure called a ‘quantum point contact’ [15–21], which structure is relatively easy to achieve using an STM. The switching operation was realized by atomically contacting and separating the STM tip and the gold particles present on the substrate electrodes. An atomic scale point contact, composed of gold atoms, was reversibly formed and annihilated by precisely moving the position of the STM tip by controlling the voltage applied to a piezoelectric element attached to the tip. Furthermore, since the width of this point contact was about the Fermi wavelength of gold, it was shown that the conductance of the point contact was the base unit of the quantized conductance (Go = 2e2/h). Here, h is Planck’s constant and e is the elementary charge. In other words, they demonstrated switching behavior between conductance in the quantized and tunneled states due to the formation and annihilation of quantized point contacts. Using a probe microscope such as an STM, an electrode needle such as a thin metal wire is brought into contact with a metal substrate and then slowly pulled away from the substrate, thereby gradually reducing the area of the point contact and allowing the structure of the point contact can be continuously changed at the atomic level. At the same time, when a slight voltage is applied to the point contact, the current changes in a stepwise fashion, and conductance of various quantized states are observed. Ohnishi et al. incorporated an STM into an ultrahigh vacuum transmission electron microscope, and used in situ observation to reveal the relationship between an atomic structure and quantum conductance just prior to the breakdown of a point contact in gold (Au) [22]. They observed bridges, consisting of several gold atoms, between the electrodes. In the structure of a single chain of Au atoms, the conductance showed the basic unit Go, and in the double chain structure, the conductance was twice as large. Quantized conductance of point contacts was also found in a two-dimensional electron gas of the AlGaAs/GaAs heterostructure of semiconductors [23,24]. In experiments using semiconductors, quantized conduction was obtained by controlling the width of conduction channels in heterostructures at the atomic level by controlling the voltage of the gate electrode.
In the above switches, which used the transport of a single Xe atom or the quantization of conductance due to the atomic structure change of the point contact, it was necessary to move the metal tip to an appropriate position using a large chip-moving platform such as an STM. It has, therefore, been difficult to develop a practical atomic scale switch using such methods. On the other hand, the atomic switch Terabe et al. have developed is an atomic scale switch that operates using a solid state ionics method. The atomic switch works by utilizing ion transport and the electrochemical reactions in a solid electrolyte (pure ionic conductor) or a mixed conductor that conducts ions and electrons. This structure can be fabricated by sandwiching a solid electrolyte or mixed conductor between electrodes, and the switching operation is made reversible by simply controlling the voltage applied between the electrodes, at room temperature and in air. Therefore, it is relatively easy to make an atomic switch device. Herein, we describe the working principle of the atomic switch based on solid state ionics. We further introduce how the atomic switch is constructed and detail the applications that have been so far been developed for it.
Source
Taylor & Francis Group is an international company originating in England that publishes books and academic journals, its parts include, Taylor & Francis, Routledge, F1000 Research or Dovepress. It is a division of Informa plc, a United Kingdom–based publisher and conference company.
Link to full article
https://www.tandfonline.com/doi/full/10.1080/23746149.2022.2065217
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