Showing papers on "AND gate published in 2022"

Realization of Ultra-Compact All-Optical Logic AND Gate Based on Photonic Crystal Waveguide

Abstract: In this article, we have proposed a design of all-optical logic AND gate in the two-dimensional photonic crystal of triangular lattice structure with silicon rods in air background medium. Introducing line defect in the crystal, a Y-shaped waveguide is created and no nonlinear material is used to construct the device. The radiuses of few rods at the junction area are optimized to realize the operation of logic AND gate. The size of the proposed device is very small with a dimension of 77 μm2 and it provides a contrast ratio of 6.9 dB. It offers a response time of 0.193 picoseconds and a data rate of 2.8 Tbit/second. Plane wave expansion method and finite difference time domain method have been applied to calculate the band structure and to analyze the performance of the simulation, respectively.

Design and numerical analysis of multifunctional photonic crystal logic gates

Abstract: All-optical multifunctional structures are at the beginning of the growth and development path to achieve an all-optical integrated circuit (AOIC). The main challenge of designing multifunctional all-optical nanostructures is to maintain the overall function of the structure compared to single-function nanostructures. Simultaneous application of logic gates of AND, XOR, half-adder, 1-bit comparator, reversible Feynman logic gate along with desirable and suitable function are some of the proposed nanostructure properties. The propagation modes in the structure are extracted by the plane wave expansion (PWE) method. The overall operation of the nanostructure, simulation, and numerical analysis of the proposed nanostructure for the submitted applications are performed using the numerical method finite-difference time-domain (FDTD). In the proposed multifunctional nanostructure, ultra-fast and ultra-compact logic gates with a maximum time delay of approximately 280 fs, an area of 104 μm2, and a bit rate of 3.57 Tb/s are provided. In addition to the proposed ultra-compact logic gate, another advantage of the proposed multifunctional nanostructure is achieving the appropriate contrast ratio.

Sensitive Logic Nanodevices with Strong Response for Weak Inputs.

Abstract: Sensitive sensing is critical when developing new calculation systems with weak input signals (ISs). In this work, a "weak-inputs-strong-outputs" strategy was proposed to guide the construction of sensitive logic nanodevices by coupling input-induced reversible DNA computing platform with hybridization chain reaction-based signal amplifier. By rational design of the sequence of computing elements (CEs) so as to avoid cross-talking between ISs and signal amplifier, the newly formed logic nanodevices have good sensitivity to the weak ISs even at low concentrations of CEs, and are able to perform YES, OR, NAND, NOR, INHIBIT, INHIBIT-OR and number classifier operation, showing that the DNA calculation proceeds in dilute solution medium that greatly prompts the calculation proficiency of logic nanodevices without the confinement of lithography process in nanotechnology.

Cascadable direct current driven skyrmion logic inverter gate

Abstract: Nanoscale skyrmions enable ultralow-power nonvolatile logic gate designs due to their current-driven motion and topological protection. A key building block in skyrmion-based digital spintronics is the logic inverter (not) gate. Despite recent computational and practical demonstrations, a skyrmion-based low-power, wideband, and cascadable inverter gate is still a long way off. For skyrmion-based logic circuits, a systematic design and analysis of an inverter gate is essential. Here we present a skyrmion logic inverter design and analyze its full operation using micromagnetic modeling. Because of the substrate thermal conductivity, our investigations reveal that the all-metallic inverter gate can function with direct current drive, wide bandwidth, submicron footprint, no or low external magnetic field, cascadability, and with room-temperature thermal stability despite Joule heating. Using magnetic insulators for eliminating Joule heating and lowering the exchange stiffness, magnetic moment and other factors might further assist in reducing power consumption by more than four orders of magnitude.

Photochromic Metallopolymer Based on Dithienylethene as a Molecular Calculator

Abstract: Switchable compounds have been often described as promising candidates for electronic applications such as molecular-scale calculators. A step further is the combination of several different switchable molecules in larger functional macromolecules to design more sophisticated Boolean logic gates. Here, complex logic devices have been built via a redox- and photoactive metallopolymer based on dithienylethene-appended iron bis-terpyridine units. The commutation of individual building blocks of the metallopolymer is achieved using light or an electrical stimulus, thus demonstrating a way to build multiswitchable molecular logic gates by a rational chemical design. This functional material exhibits five accessible and distinguishable stable states that can be used as AND and OR logic gates, as a half-adder or multiplexer.

Gate-controlled electron quantum interference logic

Abstract: Inspired by using the wave nature of electrons for electron quantum optics, we propose a new type of electron quantum interference structure, where single-electron waves are coherently injected into a gate-controlled, two-dimensional waveguide and exit through one or more output channels. The gate-controlled interference effects lead to specific current levels in the output channels, which can be used to realize logic gate operations, e.g., NAND or NOR gates. The operating principle is shown by coherent, dynamic Wigner quantum electron transport simulations. A discussion of classical simulations (Boltzmann) allows to outline the underlying process of interference. Contrary to other electron control approaches used for advanced information processing, no magnetic or photonic mechanisms are involved.

Analysis and research of all-optical logic and/or gate based on 2D photonic crystal

Abstract: Based on the ring resonator and microcavity, this paper designs a new method for realizing all-optical logic gates. Firstly, manufacture defects in complete triangular lattice silicon to produce waveguide coupling and linear interference effect. Secondly, the proposed structure was simulated by plane wave expansion method and finite difference time domain method. Finally, view the simulation results and analyze the performance index parameters of the proposed all-optical logic gate in combination with experimental data. The results show that the extinction ratio of the proposed all-optical logic AND gate can reach 8dB, the structure size is small, the response time can reach 2.42ps. At the same time, the value of the proposed all-optical logic OR gate output can reach 0.72, the structure size is small, and the response time can reach 2.41ps. The performance is favorable and meets the experimental requirements.

Sensitive Logic Nanodevices with Strong Response for Weak Inputs

Abstract: Sensitive sensing is critical when developing new calculation systems with weak input signals (ISs). In this work, a “weak-inputs-strong-outputs” strategy was proposed to guide the construction of sensitive logic nanodevices by coupling input-induced reversible DNA computing platform with hybridization chain reaction-based signal amplifier. By rational design of the sequence of computing elements (CEs) so as to avoid cross-talking between ISs and signal amplifier, the newly formed logic nanodevices have good sensitivity to the weak ISs even at low concentrations of CEs, and are able to perform YES, OR, NAND, NOR, INHIBIT, INHIBIT-OR and number classifier operation, showing that the DNA calculation proceeds in dilute solution medium that greatly prompts the calculation proficiency of logic nanodevices without the confinement of lithography process in nanotechnology.

Three‐Input Magnetic Logic Gates Using Magnetic Vortex Transistor

Abstract: Compared to the present‐day semiconductor technology in logic gates, which uses the transport properties of electrons, the magnetic analog of logic gates using magnetic vortices has proven to be advantageous in many ways due to its efficiency in terms of negligible electron power leakage and higher switching speed. Based on the asymmetric magnetic vortex transistor (AMVT), a 3‐input OR gate and a majority gate using micromagnetic simulations are demonstrated. Depending on the distances between the three‐input units and the input–output unit and the polarities of the magnetic vortices of the output unit, the networks behave as logic gates. Considering AMVT as one unit, three such units are placed parallel to the input side and another on the output side. Spin‐polarized current is applied to the input units, and the energy is transferred to the output unit owing to the movement of antivortex solitons through the magnetic stray field distribution. Energy transfer is recorded from the output unit, and any energy amplification is considered an ON (1) state, whereas a reduction in energy is considered an OFF (0) state. These “magnetic” logic gate configurations using magnetic vortices can thus behave as fundamental blocks of “magnetic” integrated circuits in the future.

2D-FDTD Electromagnetic Simulation of an Ultracompact All-Optical Logic Gate Based on 2D Photonic Crystal for Ultrafast Applications

Abstract: In this paper, the concept of photonic crystals (PhCs) is fundamental to the design and simulation of an all-optical device. The proposed logic device is composed of two-dimensional (2D) photonic crystal waveguides with a central photonic crystal ring resonator (PCRR). The new all-optical NAND logic gate is composed of two linear waveguides coupled to each other through a single compact PCRR. The plane wave expansion (PWE) and finite-difference time-domain (FDTD) methods are used to analyze the behavior of the structure that is implemented on the operational wavelength of 1700 nm on an air wafer of only 12 µm × 12 µm. The simulation results show that the proposed all-optical NAND gate is a strong candidate to be used for ultrafast photonic integrated circuits (PICs) being highly advantageous with high transmitting power, simple design and without use of the optical amplifiers and nonlinear materials.

The thermal spin molecular logic gates modulated by an electric field

Abstract: Logic gates are fundamental structural components in all modern digital electronic devices. Here, nonequilibrium Green’s functions are incorporated with the density functional theory to verify the thermal spin transport features of the single-molecule spintronic devices constructed by a single molecule in series or parallel connected with graphene nanoribbons electrodes. Our calculations demonstrate that the electric field can manipulate the spin-polarized current. Then, a complete set of thermal spin molecular logic gates is proposed, including AND, OR, and NOT gates. The mentioned logic gates enable different designs of complex thermal spin molecular logic functions and facilitate the electric field control of thermal spin molecular devices.

Tuning current plateau regions in parallelized single-electron pumps

Abstract: The parallelization of single-electron pumps is a promising method to increase the quantized current level produced from a semiconductor-based single-electron system. In the parallelization of multiple pumps with common gate electrodes, the key process is to fabricate them with high reproducibility, resulting in an overlap of the most accurate regions in current plateaus at the same gate voltages. However, because of the lack of gating reproducibility, we here adopted a separate gate-tuning scheme to realize the overlap of the current plateaus instead of using a common gate scheme. To minimize the number of gates, we used entrance gates in common but an exit gate in separate with an additional in-common gate located outside the quantum dot but near the exit gates. The combination of the additional gate and separate exit gates led to an optimal current plateau overlap with a pair of pumps among six pumps in parallel. Under the optimal plateau-tuned condition, we achieved a relative type-A uncertainty of 1.4 × 10−6 at a 100 pA level with f = 160 MHz in the parallelized mode with the second current plateaus for both pumps.

Design of an all-optical multi-logic operation-integrated metamaterial-based terahertz logic gate.

Abstract: Terahertz logic gates play a vital role in optical signal processing and terahertz digitization. Herein, a strategy to design an all-optical terahertz logic gate device composed of metamaterials with a semiconductor-metal hybrid is proposed; accordingly, a concrete logic gate composed of Ge embedded-in Au stripe supported by a Si board is presented theoretically. Simulation results reveal the dependence of the terahertz transmission spectra on the different illuminations in the device. Based on the illumination-transmission response, the designed device can realize the NOR or OR Boolean operation. The effects of the width of the Ge-Au stripe as well as the Si board on the transmission spectra and logic performance were also investigated.

Gate-controlled electron quantum interference logic

Abstract: Inspired by using the wave nature of electrons for electron quantum optics, we propose a new type of electron quantum interference structure, where single-electron waves are coherently injected into a gate-controlled, two-dimensional waveguide and exit through one or more output channels. The gate-controlled interference effects lead to specific current levels in the output channels, which can be used to realize logic gate operations, e.g., NAND or NOR gates. The operating principle is shown by coherent, dynamic Wigner quantum electron transport simulations. A discussion of classical simulations (Boltzmann) allows to outline the underlying process of interference. Contrary to other electron control approaches used for advanced information processing, no magnetic or photonic mechanisms are involved.

Design and research of logic gate based on photonic crystal self-collimation effect

Abstract: Based on polarization independent optical splitters and beam splitters, a new logic gate design method based on self collimation effect is proposed. Using the characteristics of light self-collimation transmission in the photonic crystal, combined with the optical splitter, the optical path difference is introduced, so that the corresponding phase difference between the incident light is generated. It makes the light beam produce interference effect at the beam splitter converge, so as to realize the logic function of NOR gate, NAND gate and XOR gate. Simultaneously, the plane wave expansion method and the finite difference time domain method are used to simulate and analyze the logic gate in the TM polarization mode to verify its logic function. The analysis of the results shows that the logic gate designed by self-collimation effect and linear interference is compact, smaller in size, easy to manufacture, short in time response, high in transmittance, and more suitable for the development of optical integration.

Analytical subthreshold current model of the dual-material tri-gate (DMTG) MOSFET and its application for subthreshold logic gate

Abstract: Multi-gate MOSFETs are considered for realizing ultra-low-power circuits due to their superior channel control capability and short channel effect (SCE) resistance. To achieve this goal, it is necessary to establish a suitable compact device circuit model for them. However, current research focuses more on single-material multi-gate MOSFET, and there is no research report on dual-material logic gates. In this work, we develop a subthreshold current model for dual-material tri-gate (DMTG) MOSFET. It is found that the gate metal close to the source can affect the subthreshold characteristics of the transistor to a greater extent. Moreover, combined with the equivalent transistor model, the noise margin (NM) model of the subthreshold inverter composed of DMTG MOSFETs is developed. The nearly equal NM can be obtained by equal NM design (END). An appropriate work function can be selected through END to obtain the optimal NM when designing the inverter. The NM under different device geometric parameters is given, and the simulation result shows that the model accuracy reaches 98%. Finally, the effect of DMTG structure on the device drain induced barrier lowering (DIBL) is given, which effectively reduces DIBL by 42%. These models still remain high accuracy when the device channel length shrink down to 20 nm, which provide the possibility for DMTG MOSFET to be effectively applied to ultra-low-power circuits.

New structure for an all-optical logic gate based on hybrid plasmonic square-shaped nanoring resonators and strips

Abstract: Abstract Seven all-optical logic gates based on hybrid plasmonic squared-shaped nanoring resonators and strips are proposed, designed, and numerically analyzed using Finite Element Method (FEM) with COMSOL software package. Constructive and destructive interferences between the input port(s) and the control port(s) are the main operating principles used to produce the proposed gates. The ratio of output optical power to the input power at a single port which is called the transmission threshold is selected to be 30% and the resonance wavelength is 1310 nm. All the hybrid plasmonic logic gates are performed in a single structure of 400nm x 400 nm dimensions and the performance is measured according to the values of transmission at the output port versus a wavelength range from 800 nm to 2000 nm, contrast ratio, modulation depth, and insertion loss. The transmission exceeds 100% in five gates, 146% at NOT and NAND gates, 202.3% at OR, AND, and XNOR gates. The modulation depth scores are 99.75% at the XNOR gate, 98.5% at the NOR gate, 97.67% at OR, AND, NOT, and NAND gates, and 95.29% for the XOR gate.