Logic Devices Research Articles

Built-in Analog Automatic Controls for Small Robots

One of the most promising methods for improving control efficiency is the parallel synthesis of commands by a group of computing devices. However, delays in digital-to-analog conversions and software processing, the need to synchronize calculations, and signal transmission coordination prevent the achievement of maximum performance in distributed systems. Problems can be solved by increasing the power of embedded microprocessors. This leads to an undesirable increase in design complexity, energy consumption, and dimensions of controls. For the miniaturization of embedded control systems, the article proposes to apply the principles of the indivisibility of physical processes in a technical system and the execution of control commands based on the functional combination of aggregates with analog logic devices (agents). A generalized model of changing the states of a technical system is considered, which sets the principles for switching on or off groups of units. The concept of an automaton of ternary logic is introduced, which determines the order of interaction of aggregates in the time domain. The synthesis of the block diagram of the automaton is carried out. In the mathematical model of the automaton, the operations of ternary logic receive a specific physical content in the form of retrospective processing of changes in the states of aggregates. It is shown that ternary logic automata can be combined into open and closed chains, setting hardware control algorithms units robot. The circuits for connecting automata controlled by elements of asynchronous logic are given. When connected in series, the automata control the order of switching on and off the units. Chains of three-valued logic automata can be arbitrarily long, determining the behavior of the system in the process of its operation. Due to the rejection of program control, such automata can operate in real time, limited only by the delay of signals in logic elements. An important advantage of the proposed technical solution is the unification of the automatic control system. The simplicity of the design of devices and the absence of additional add-ons make it possible to integrate such circuits into the controls of microminiature robots, reducing their weight and size parameters. Promising areas of application of analog automata are microelectromechanical and microelectronic devices.

Dynamic behavior of skyrmion collision: spiral and breath

A magnetic skyrmion is a particle-like topological soliton, which is an ideal candidate for developing high-density storage and logic devices due to its nonvolatility and tunability. In view of the particle motion characteristics of skyrmion, different skyrmions in a material inevitably interact in the form of short-range repulsion and long-range attraction. In this work, the dynamic characteristics of skyrmion collision in a ferromagnetic Co thin film are investigated by using micromagnetic simulations. It is found that the dynamic behavior of skyrmion after collision is highly dependent on the size of the strip, the initial velocity of skyrmion and magnetic damping constant. For the collision of two skyrmions, when the strip width exceeds the critical value, the skyrmions form a pair and rotate counterclockwise in the form of spiral and breath. It is interesting that the rotation and breath of skyrmions keep the same periodicity under the negligible damping, and the frequency increases with the increase of the initial velocity of skyrmion. Further, the collision of a system of three skyrmions reveals that they interact in pairs to form closed periodic trajectories. The results of the present work not only give an insight into the multi-skyrmion dynamics, but also provide guidance for the development of spintronic devices based on multi-skyrmion motion.

Ferroelectric gating of two-dimensional semiconductors for the integration of steep-slope logic and neuromorphic devices

Ferroelectric gating of two-dimensional semiconductors for the integration of steep-slope logic and neuromorphic devices

Designing Next‐Generation Molecular Logic Circuits: Photonic Concatenation in Upconverting Nanocrystals

AbstractComputers and computing systems are getting an increasingly essential role in society, as revealed by the current emergence of Artificial Intelligence. The further increase in computer systems and digitalization of society will certainly demand innovative computing systems with higher processing speeds at low energetic and capital costs. Remarkable developments in the last five years have been reported for quantum computing; nevertheless, photonic and molecular computing has also been evolving with the potential of reaching the maximum possible miniaturization by using molecules as building blocks for basilar logic systems. One of the main challenges for molecular logic is the logical connection between molecular elements, called concatenation. Until now, concatenation of molecular logic gates has been exclusively reported using chemical species, with obvious practical limitations. In this work, the first photonic concatenation of a NAND with an AND molecular logic gate is presented. The logic system is implemented on nanoplatforms of Yb3+/Er3+ core@shell Sr2YF7 nanocrystals that are used to define combinatory logic gates and temperature‐reconfigurable logic systems. The results show that upconverting nanocrystals are promising platforms for the development of solid‐state molecular logic devices. These devices can reproduce the logical operations that are currently implemented in electronic devices.

Wide-range and area-selective threshold voltage tunability in ultrathin indium oxide transistors

The scaling of transistors with thinner channel thicknesses has led to a surge in research on two-dimensional (2D) and quasi-2D semiconductors. However, modulating the threshold voltage (VT) in ultrathin transistors is challenging, as traditional doping methods are not readily applicable. In this work, we introduce a optical-thermal method, combining ultraviolet (UV) illumination and oxygen annealing, to achieve broad-range VT tunability in ultrathin In2O3. This method can achieve both positive and negative VT tuning and is reversible. The modulation of sheet carrier density, which corresponds to VT shift, is comparable to that obtained using other doping and capacitive charging techniques in other ultrathin transistors, including 2D semiconductors. With the controllability of VT, we successfully demonstrate the realization of depletion-load inverter and multi-state logic devices, as well as wafer-scale VT modulation via an automated laser system, showcasing its potential for low-power circuit design and non-von Neumann computing applications.

Mg‐Zn Ferrite Nanoparticles: A Brief Review on Synthesis, Characterizations, and Applications

AbstractFerrites are of great interest for both fundamental science and technological applications due to their outstanding physical, chemical, and magnetic properties. Among various ferrites, Mg‐Zn ferrites is one of the best magnetic materials for researchers due to their unique properties such as high electric resistivity, Curie temperature, low coercivity, low eddy current, dielectric losses, low cost, and better environmental stability. This makes ferrites suitable for many applications such as power transformers, microwave devices, computer memories, logic devices, recording heads, loading coils, antenna rods, color monitoring tubes, telecommunications, hyperthermia, and so forth. Mg‐Zn ferrite nanoparticles have gained increased interest for many applications such as catalysts, antimicrobial potential, and sensors for the detection of combustible gases (CH4, CO, and CO2). In this brief review, the strategies used in the synthesis of Mg‐Zn ferrite nanoparticles are summarized. The different structural, morphological, magnetic, and electric properties of these ferrites are analyzed.

Carbon-based cryoelectronics: graphene and carbon nanotube

The rise of quantum computing has prompted the interest in the field of cryogenic electronics. Carbon-based materials hold great promise in the area of cryogenic electronics due to their excellent material properties and emergent quantum effects. This paper introduces the advantages of carbon-based materials for cryogenic applications and reviews recent progress in carbon nanotubes and graphene for logic devices, sensors and novel quantum devices at cryogenic temperatures. Finally, the main challenges and extensive prospects for the further development of carbon-based cryoelectronics are summarized.

Electrically-Excited Motion of Topological Defects in Multiferroic Materials

Topological magnetic defects in multiferroic materials acquire an electric charge or dipole moment due to the inverse Dzyaloshinskii-Moriya mechanism. This magnetoelectric coupling makes possible to excite large-amplitude collective motion of topological magnetic textures with an oscillating electric field. Here, I discuss electric excitation of a polar optical mode in a vortex-antivortex crystal and the electrically-induced spin precession in a magnetic skyrmion, which gives rise to rotation of skyrmions around each other and a translational motion of skyrmion-antiskyrmion pairs. The electric manipulation of magnetic topological defects in Mott insulators can find applications in magnetoelectric memory and logical devices.

From Zeno ad infinitum: Iterative Reasonings in Early Greek Philosophy

Abstract This paper considers some aspects of the early conception and use of the infinite in ancient Greece, in the spirit of recent results in the history of ancient mathematics. It follows aspects of the practice of reasoning ad infinitum from the extant corpus of and about Zeno of Elea up to early Hellenistic examples in Aristotle and Euclid. Starting with the idea of ‘reasoning from indefinite iteration’, based on the metalogical recognition of the unachievability of an inference process, it identifies several different classes of more or less sophisticated arguments that make use of this idea, and examines the logical devices and notions required for their acceptance in the philosophical practice. Those include ‘Infinite regress’ properly speaking, where Non-Contradiction is used in the formation of indirect infinitary arguments.

Modulation of carrier transport in bipolar response BDD/SnO2 p+-n heterojunction UV photodetectors

A unique band-to-band tunneling (BTBT) phenomenon has been discovered in heavily boron-doped diamond (BDD)/SnO2 p+-n heterojunctions. This phenomenon can be modulated by varying the bias voltage, changing the thickness of the SnO2 film, and adjusting the power density of incident UV light. The near-broken-gap band alignment of the BDD/SnO2 heterojunction and the existence of electrons in degenerate states in the valence band of BDD are the key to achieving BTBT. Moreover, BDD/SnO2 p+-n heterojunction UV photodetectors (PDs) prepared by radio-frequency magnetron sputtering exhibit a binary photoresponse, large open-circuit voltage (Voc-l), and high photo/dark current ratio (Ip/Id). Those behaviors can be produced through periodic on/off UV light irradiation and by changing tunneling, drift, and thermionic emission currents. Our work, which is the first to achieve a binary photoresponse by modulating BTBT in BDD/SnO2 heterojunctions, demonstrates the feasibility of extending BTBT theory to logical optoelectronic devices.

Design of two different functional molecular logic devices based on hybrid fluorescence resonance­electron exchange energy transfer

Faster and more convenient construction of different functional multi-input–multi-output molecular logic devices has become a current research hotspot. In this study, a complex was synthesized using bovine serum albumin (BSA) and hydrazide dihydroxydisalicylaldehyde by a combinatorial approach. Then, the interaction mechanism was investigated by fluorescence spectroscopy and molecular simulation. Both methods revealed that the interaction between BSA and hydrazide dihydroxydisalicylaldehyde mainly occurred at site I of BSA. The main types of interactions included hydrogen bonding and van der Waals forces. Based on hybridized fluorescence resonance and electron exchange energy transfer, the complex generated two fluorescence emission peaks. Then, a digital comparator and a molecular logic circuit were designed using different metal ions or pH to modulate the output signals. Notably, the apparent increase in the fluorescence lifetime of the donor serves as an important basis for electron exchange between the donor and the acceptor.

Self-Vibration of a Liquid Crystal Elastomer Fiber-Cantilever System under Steady Illumination.

A new type of self-oscillating system has been developed with the potential to expand its applications in fields such as biomedical engineering, advanced robotics, rescue operations, and military industries. This system is capable of sustaining its own motion by absorbing energy from the stable external environment without the need for an additional controller. The existing self-sustained oscillatory systems are relatively complex in structure and difficult to fabricate and control, thus limited in their implementation in practical and complex scenarios. In this paper, we creatively propose a novel light-powered liquid crystal elastomer (LCE) fiber-cantilever system that can perform self-sustained oscillation under steady illumination. Considering the well-established LCE dynamic model, beam theory, and deflection formula, the control equations for the self-oscillating system are derived to theoretically study the dynamics of self-vibration. The LCE fiber-cantilever system under steady illumination is found to exhibit two motion regimes, namely, the static and self-vibration regimes. The positive work done by the tension of the light-powered LCE fiber provides some compensation against the structural resistance from cantilever and the air damping. In addition, the influences of system parameters on self-vibration amplitude and frequency are also studied. The newly constructed light-powered LCE fiber-cantilever system in this paper has a simple structure, easy assembly/disassembly, easy preparation, and strong expandability as a one-dimensional fiber-based system. It is expected to meet the application requirements of practical complex scenarios and has important application value in fields such as autonomous robots, energy harvesters, autonomous separators, sensors, mechanical logic devices, and biomimetic design.

Manipulation of spin–orbit torque and Dzyaloshinskii-Moriya interaction by varying Mn concentration in Pt1-xMnx/Co bilayer

Reducing critical current density (JC) of current-driven magnetization switching via power-efficient spin–orbit torque (SOT) is a key challenge in spin-based memory and logic devices. The Pt1-xMnx alloy shows prospect for enhancing the damping-like SOT efficiency (ξDL) while maintaining relatively low resistivity and power consumption. In this work, we investigated the Mn concentration x dependence of ξDL in Pt1-xMnx/Co bilayer and observed a nonmonotonic variation with the maximum ξDL ≈ 0.25 appearing around x = 0.2. The increase of the Pt1-xMnx layer resistivity is the main contribution to the enhancement of ξDL. Mn atoms doped in Pt not only modulate ξDL originating from the spin Hall effect of the Pt1-xMnx layer, but also affect the interfacial phenomena at the Pt1-xMnx/Co interface. We find that the related interfacial Dzyaloshinskii-Moriya interaction (DMI) is also tunable by x with the maximum appearing around x = 0.15. The significantly reduced JC of Pt1-xMnx/Co bilayer is mainly due to the enhancement of ξDL and the attenuation of effective perpendicular magnetic anisotropy energy density. Meanwhile, Pt1-xMnx/Co bilayer maintains low power consumption and necessary thermal stability. Our work highlights the potential of alloying Pt with Mn as a valuable means to achieve high-performance SOT spintronic devices.

Strain-enabled defect migration and defect activation in monolayer MoS2

Two-dimensional (2D) materials possess remarkable strain tolerance and exhibit strain-tunable properties, making them highly promising for flexible device applications. Defects within these materials significantly impact their optoelectronic response to strain. In this study, we investigate the influence of strain on the electrical properties of monolayer MoS2, emphasizing the pivotal role played by intrinsic defects in shaping the material’s electrical and optoelectronic response under strain. We observed an enhancement in photocurrent and persistent photoconductivity at specific strains, indicating the activation of defects at these strain values, thus enhancing the photoresponse. Moreover, our device exhibits diodic behavior at specific strain values after prolonged measurements under a static field, suggesting a reduction in the migration energy of defects caused by the applied strain. This finding holds significant implications for memory, logic, and flexible devices. Additionally, we observe an increase in electron mobility under tensile strain, with our flexible field-effect transistor exhibiting higher mobility (∼38 cm2 (V·s)−1) at 0.4% strain. Our study provides insight into the role of strain in the activation and migration of defects in monolayer MoS2 and opens up new avenues for the development of multifunctional ultra-thin flexible devices and memory applications.

Construction of a logic gate sensitive monitoring system of Graphdiyne/Poly(N,N-dimethylacrylamide) binary structure films for environmental pollutant phenylhydrazine

In this work, binary hydrogel films based on Graphdiyne/Poly(N,N-dimethylacrylamide (GDY/PDEA) were successfully polymerized and assembled on pyrolytic graphite (PG) electrode surface. When phenylhydrazine (PHz) as an active electrochemical probe in solution exhibits reversible cyclic voltammetric (CV) behaviors in response to temperature, salt and pH at the membrane electrode. The CV signals of PHz were significantly enhanced by electrocatalysis of GDY layer of the films. And the mechanism of membrane reaction was discussed and studied. The presence of protonated PHz determines the pH-sensitive property of the system. During pH adjustment with esterase urease, in situ enzymatic electrocatalysis that may be accelerates the electron transfer rate at the electrode surface. The structural alterations of PDEA hydrogels under multiple conditions were attribute to the temperature response and salt concentration–response. GDY films can also have an effect on the CV response signals. In conclusion, a multi-stimulus response hydrogel film environmental sensor has been constructed, and a 5-input/5-output logic gate system including OR, AND and NOT has been successfully constructed. And constructed 2-to-4 decoder and 2-to-1 encoder two logic devices. It provides a new method to increase the complexity of the environmental pollutant monitoring calculation system.

Factors that cause the occurrence of Computer Vision Syndrome (CVS) complaints in a person: A literature review

Computer Vision Syndrome as a complex eye and vision complaint experienced when using a computer. CVS is a compound eye experiences when using a computer. Nothing can explain the exact cause of CVS because including individual factor, environmental factors and computer factors. The purpose of this study was to identify the factors that influence the occurrence of Computer Vision Syndrome (CVS) complaints in a person. The research method utilized is a literature review, which involves searching for research articles from the electronic database Google Scholar and Research Gate using keywords such as Computer Vision Syndrome, causative factor, eye complaints, individual factor, and length of computer use. From the results of the study, it can be concluded that CVS complaints are caused by factors such as length of time working at the computer (2 articles), length of rest after using the computer (3 articles), length of computer use (2 articles), duration of computer use (3 articles), and viewing angle of the computer screen (1 article).

An elaborate biomolecular keypad lock based on electrochromism of viologen derivatives and bioelectrocatalytic reduction of CO2 at supramolecular hydrogel film electrodes

Herein, the short peptide N-fluorenemethoxycarbonyl diphenylalanine (Fmoc-FF) was used to immobilize both diallyl viologen (DAV) and the enzyme formate dehydrogenase (FDH) to form Fmoc-FF/DAV/FDH supramolecular hydrogel films on an electrode surface by a simple solvent-controlled self-assembly method. The DAV component in the films exhibited multiple properties, such as electrochromism and electrofluorochromism, and acted as an electrochemical mediator. A high efficiency of bioelectrocatalytic reduction of CO2 to formate (HCOO−) was obtained by the natural FDH enzyme and the artificial coenzyme factor DAV both immobilized in the same films. The supramolecular hydrogel films with CO2, voltage and light as stimulating factors and current, fluorescence and UV–vis extinction as responsive signals, were further applied for the construction of complex biomolecular logic systems and information encryption. A 3-input/7-output biomolecular logic gate and several logic devices, including an encoder/decoder, a parity checker, and a keypad lock, were constructed. Especially, the biomolecular keypad lock with 3 types of signals as outputs significantly enhanced the security level of information encryption. In this work, a supramolecular self-assembly interface was simply fabricated with complex biomolecular computational functions using immobilized molecules as the computational core, greatly broadening the application range of supramolecular hydrogel films and providing an idea for new designs of bioinformation encryption through the use of a simple film system.

Enhanced electrodynamic gating in two-dimensional transistors using ferroelectric capping

Two-dimensional (2D) materials such as semiconductors and ferroelectrics are promising for future energy-efficient logic devices because of their extraordinary electronic properties at atomic thickness. In this work, we investigated a van der Waals heterostructure composited of 2D semiconducting MoS2 and 2D ferroelectric CuInP2S6 (CIPS) and NiPS3. Instead of using 2D ferroelectrics as conventional gate dielectric layers, here we applied CIPS and NiPS3 as a ferroelectric capping layer, and investigated a long-distance coupling effect with the gate upon the sandwiched 2D MoS2 channels. Our experimental results showed an outstanding enhancement of the electrodynamic gating in 2D MoS2 transistors, represented by a significant reduction of subthreshold swing at room temperature. This was due to the coupling-induced polarization of 2D ferroelectrics at 2D semiconductor surface which led to an effective and dynamic magnification of the gate capacitance. Meanwhile, the electrostatic gating was remained steady after adding the ferroelectric capping layer, providing ease and compatibility for further implementation with existing circuit and system design. Our work demonstrates the long-distance coupling effect of 2D ferroelectrics in a capping architecture, reveals its impacts from both electrodynamic and electrostatic perspectives, and expands the potential of 2D ferroelectrics to further improve the performance of energy-efficient nanoelectronics.

Magnetic Field and Temperature-Dependent Brillouin Light Scattering Spectra of Magnons in Yttrium Iron Garnet.

Knowledge of the magnon responses to an external magnetic field and temperature is significant for spintronics applications. Herein, exploiting Brillouin light scattering (BLS) spectroscopy, we investigate the magnetic field and temperature dependence of the magnon frequency, line width, and intensity in yttrium iron garnet (YIG). The applied magnetic field here can effectively change the magnon frequency while maintaining the lifetime of the magnon. Specifically, we determine the temperature dependence of magnon frequency and the linear relationship between magneto-optic effects-related terms (|A(+)|2/|A(-)|2) and temperature below room temperature (RT), which can serve as a temperature sensor. Our results open an avenue to sense the temperature and the external magnetic field, including the effective magnetic field induced by the magnetic proximity effect. Furthermore, our results provide a route toward designing the operating frequency and loss of the devices, facilitating future research in spin-related applications, including magnon-based logic, memory, sensing, and thermospin devices.

Boolean Logic Computing Based on Neuromorphic Transistor

AbstractGeneral‐purpose computers usually use logic gate computing units based on complementary metal oxide semiconductors (CMOS). Due to the separate memory and computing units in Von Neumann architecture, data transmission requires great energy and time consumption. Developing novel neuromorphic devices and comprehensively investigating their logical computing mode are crucial to achieve high‐performance and low‐power neuromorphic computation. Here, a systematic summary of Boolean logic computing based on emerging neuromorphic transistors is presented. This summary encompasses logical operation modes, materials, device structures, and working mechanisms. The input mode of Boolean logic operation is classified into electrical input, optical input, and synergistic optical/electrical input. Besides, additional modulation strategies to construct programmable logic functions by electrical, optical, and thermal signals are also summarized. These strategies hold great significance as they enable dynamic reconfiguration of logic operations and provide neuromorphic devices with decision‐making capabilities. Finally, the application prospects and current challenges to Boolean logic computing based on dendritic integration are discussed from the aspects of device integration, synergistic input/modulation modes, auxiliary peripheral circuit, software/hardware system, etc. It is believed that comprehensive investigations on neuromorphic Boolean logic operations are crucial to push forward the development of future neuromorphic computing toward high efficiency and high integration density.