Memory Elements Research Articles

Resistive switching in emerging materials and their characteristics for neuromorphic computing

Resistive random access memory (ReRAM) would be an important component of microelectronics in the era of big data storage due to its efficient characteristics such as low cost, fast operating speed, low power consumption, and high performance in respect of endurance and retention. In this present review, we have focused on surveying three physical mechanisms which lead to resistive switching: electrochemical metallization, valence change mechanism, and ferroelectric polarization. A detailed discussion has been carried out on how these physical mechanisms work in various materials used for resistive switching based on nonvolatile random access memory (NVRAM) elements such as oxides, ferroelectric, chalcogenides, polymers, graphene-based resistive switching, etc. The desirable electrical and optical properties for the representation of analog resistive switching in neuromorphic computing have also been discussed. An extensive report has examined the device requirement of different materials for artificial memristors.

A Hierarchically Encoded Data Storage Device with Controlled Transiency (Adv. Mater. 20/2022)

Data-Storage Devices In article number 2201035, Jianxing Li, Tiger H. Tao, Zhitao Zhou, and co-workers demonstrate an implantable silk-based hierarchically encoded data-storage device with controlled transiency. Resistive random-access memory, terahertz metamaterials, and diffractive optical elements are vertically integrated to store electronic, photonic, and optical information. The hierarchical degradation modes realized by different solvents can greatly increase the storage capacity and information encryption.

Minimizing Subtle Errors in Computing Information of TCAM by Partial “N” Search Key Implementation

The primary memory of the computer gets corrupted due to microparticles that possess a great deal of energy. This causes transient kind of errors and it is called subtle errors. High corruption of data in computer systems has been occurred because of these errors. Major sources of subtle errors include ionic particles, huge radiations say example alpha, beta and gamma rays, protons, neutrons etc., When TCAM configuration changes from 120 nm to 20 nm technology, there was a drastic increase in subtle errors more than multiples of eight. Devices operated in low power regions are more prone to subtle errors. Memory storage devices like secondary memory element called cache, registers are more feasible to subtle errors. 1 Behavior of subtle errors never damage circuit configuration but changes the information content leading to erroneous data. The proposed architecture is called N-SEARCH KEY TCAM, where in this system, it has been predicted that occurrence of subtle errors are very small. This innovative method of detecting and correcting both single and burst type of subtle errors has many modules like TCAM, Multiplexer, control circuit and Error correction code frame. Moreover, the proposed architecture N-SEARCH KEY ternary memory uses a special LUT for matching process. A key named Search key was generated which contains don’t care bits for matching subtle errors. Unlike regular TCAM, this design uses sequential LUT which enhances matching time of order [Formula: see text](wnlog2[Formula: see text]. Initially, proposed scheme have been used to find single bit subtle errors by changing forbearance factor ([Formula: see text] and chances of occurrence of error among TCAM information. The design was enhanced to detect multiple subtle errors and rectified the same. If match not occurs with predetermined information, then IP filter forbids the unauthorized users from using global network resources, thus providing better information security. By the proposed method, number of improper segregation ratio decreases with increase in Forbearance ratio parameter and time required to detect and correct the same is also considerably reduced. By controlling the forbearance factor [Formula: see text], the best duration schemes can be chosen. Through the given architecture, average time consumption for error checking of subtle errors would range from 0.6 to 0.7 [Formula: see text]s.

Neuromorphic Implementation of Logic Functions Based on Parallel Dual-Gate Thin-Film Transistors

Composed of computation units each containing a parallel, dual-gate (DG) thin-film transistor (TFT) and a memory capacitor addressed by an access TFT, a neuromorphic circuit implementing fundamental AND and OR logic functions is realized and characterized. The exceptionally low leakage current of a TFT built on indium-gallium-zinc oxide (IGZO) allows the capacitor to be used as a quasi-static memory element. Appropriate weight signals for the realization of the two logic functions are obtained using a gradient-descent training algorithm. The circuit can be configured to execute one of the two functions by the setting of the weight signals.

Behavioral Studies of p62 KO Animals with Implications of a Modulated Function of the Endocannabinoid System.

Elementary emotional states and memory can be regulated by the homeostasis of the endocannabinoid system (ECS). Links between the ECS and the autophagy receptor p62 have been found at the molecular level and in animal studies. This project aimed to validate the anxiety and memory phenotype of p62 knockout (KO) animals and whether the ECS plays a role in this. We examined the behavior of p62 KO animals and analyzed whether endocannabinoid levels are altered in the responsible brain areas. We discovered in age-dependent obese p62 KO mice decreased anandamide levels in the amygdala, a brain structure important for emotional responses. Against our expectation, p62 KO animals did not exhibit an anxiety phenotype, but showed slightly increased exploratory behavior as evidenced in novel object and further tests. In addition, KO animals exhibited decreased freezing responses in the fear conditioning. Administration of the phytocannabinoid delta9-tetrahydrocannabinol (THC) resulted in lesser effects on locomotion but in comparable hypothermic effects in p62 KO compared with WT littermates. Our results do not confirm previously published results, as our mouse line does not exhibit a drastic behavioral phenotype. Moreover, we identified further indications of a connection to the ECS and hence offer new perspectives for future investigations.

Comparative Analysis Of CNTFET Based SRAM Cells

Due to the distinctive ability of retaining the data, SRAM is the most prominent memory element used in many electronic devices. The fundamental limits faced by the CMOS technology below 10nm, restricts its relevancy in terms of power consumption, size and speed. Therefore considerable concentration is focused on an alternate technology i.e CNTFET especially for low power designs. This paper mainly focuses on the comparative analysis of different CNTFET based SRAM cells like 6T, 7T, 8T, 9T and 10T. The comparison is done with respect to Power consumption, delay and Noise Margin.

Experimental validation of state equations and dynamic route maps for phase change memristive devices

Phase Change Memory (PCM) is an emerging technology exploiting the rapid and reversible phase transition of certain chalcogenides to realize nanoscale memory elements. PCM devices are being explored as non-volatile storage-class memory and as computing elements for in-memory and neuromorphic computing. It is well-known that PCM exhibits several characteristics of a memristive device. In this work, based on the essential physical attributes of PCM devices, we exploit the concept of Dynamic Route Map (DRM) to capture the complex physics underlying these devices to describe them as memristive devices defined by a state—dependent Ohm’s law. The efficacy of the DRM has been proven by comparing numerical results with experimental data obtained on PCM devices.

Adaptive Biosensing and Neuromorphic Classification Based on an Ambipolar Organic Mixed Ionic-Electronic Conductor.

Organic mixed ionic-electronic conductors (OMIECs) are central to bioelectronic applications such as biosensors, health-monitoring devices, and neural interfaces, and have facilitated efficient next-generation brain-inspired computing and biohybrid systems. Despite these examples, smart and adaptive circuits that can locally process and optimize biosignals have not yet been realized. Here, a tunable sensing circuit is shown that can locally modulate biologically relevant signals like electromyograms (EMGs) and electrocardiograms (ECGs), that is based on a complementary logic inverter combined with a neuromorphic memory element, and that is constructed from a single polymer mixed conductor. It is demonstrated that a small neuromorphic array based on this material effects high classification accuracy in heartbeat anomaly detection. This high-performance material allows for straightforward monolithic integration, which reduces fabrication complexity while also achieving high on/off ratios with excellent ambient p- and n-type stability in transistor performance. This material opens a route toward simple and straightforward fabrication and integration of more sophisticated adaptive circuits for future smart bioelectronics.

Spin-Crossover in Supramolecular Iron(II)-2,6-bis(1H-Pyrazol-1-yl)pyridine Complexes: Toward Spin-State Switchable Single-Molecule Junctions.

Spin-crossover (SCO) active iron(II) complexes are an integral class of switchable and bistable molecular materials. Spin-state switching properties of the SCO complexes have been studied in the bulk and single-molecule levels to progress toward fabricating molecule-based switching and memory elements. Supramolecular SCO complexes featuring anchoring groups for metallic electrodes, for example, gold (Au), are ideal candidates to study spin-state switching at the single-molecule level. In this study, we report on the spin-state switching characteristics of supramolecular iron(II) complexes 1 and 2 composed of functional 4-([2,2′-bithiophen]-5-ylethynyl)-2,6-di(1H-pyrazol-1-yl)pyridine (L1) and 4-(2-(5-(5-hexylthiophen-2-yl)thiophen-2-yl)ethynyl)-2,6-di(1H-pyrazol-1-yl)pyridine (L2) ligands, respectively. Density functional theory (DFT) studies revealed stretching-induced spin-state switching in a molecular junction composed of complex 1, taken as a representative example, and gold electrodes. Single-molecule conductance traces revealed the unfavorable orientation of the complexes in the junctions to demonstrate the spin-state dependence of the conductance.

AMPS: An Automated Mesochronous Pipeline Scheduler and Design Space Explorer for High Performance Digital Circuits

In the Mesochronous Pipeline (MP), the clock period is the maximal of differences between the maximum/minimum delays of all stages. This value is less than the maximum delay between the memory elements, so MP is operating faster than the conventional pipeline (CP). To take full advantages of MP, in this paper, Automated Mesochronous Pipeline Scheduler (AMPS) for high performance digital circuits, is proposed which provides all allowed partitioning options generated by register allocation procedures obtained with varying maximum delay differences of stages. This allows a designer to select from design space produced by AMPS based on the desired specification. Unlike the traditional MP, AMPS utilizes automated scripts to extract the timing characteristics of the synchronizers and gates. This enables a designer to explore trade-offs between latency, power, and frequency. To evaluate our toolset, an 8-bit Carry Increment Adder (CIA), a 4-bit Binary-Coded Decimal (BCD) adder, a 4-bit ALU, and a set of circuits from ISCAS85 and ISCAS89 benchmarks are considered. All circuit level simulations are performed in the 65nm CMOS standard technology node. AMPS improves the frequency for its best solutions about 127.94% (on average) in comparison to the conventional pipeline scheme.

Mimesis and the Process of Becoming Human: Performativity, Repetition and Practical Knowledge

Although mimetic processes play an important role in the aesthetic experiences of art, literature, music, and theatre, they are also important in other areas. Mimetic processes are central to how human beings develop into humans. Plato and Aristotle were among the first to point this out. More recently, this ancient insight has been confirmed by research in evolutionary anthropology, neuroscience, and cultural anthropology. Cultural learning is essentially mimetic learning. It ensues through relationships with other people, as well as with nature, cultural objects, and artifacts. Hence, mimesis is of central importance for the development of cultural and practical knowledge. In this article, I argue that mimetic processes are processes of repetition and as such they are key elements both of memory and innovative action. They pave the way for innovations in post-literary cultures where a mimetic turn, or re-turn of attention to mimetic processes, is currently underway.

Study, implementation and testing of radiation tolerant design for testability solutions for CMS OT FE ASICs

The MPA and SSA development is approaching the production phase with an approximate volume of more than 200k ASICs, corresponding to 1200 wafers. The limited manufacturing yield requires testing strategies able to identify defective units and guarantee the correct functionality of the tracker modules. This contribution presents innovative methods to replace the currently used functional tests for the digital part of the ASICs, showing limited testing accuracy and long testing time. The proposed solution exploits the concept of structural test and new testing algorithms such as Automatic Test Pattern Generation (ATPG) for general digital logic and March for memory elements. Design for Testability (DFT) hardware is integrated on chip to test SRAM memories, peripheral logic and MPA pixel array, providing internal control and observation points for the implementation of the those algorithms. Particular attention is given to power increase, timing and placement impact as well as radiation tolerance of the introduced circuitry, which must be fully transparent during the normal operation of the chip. A faster and more accurate testing approach is presented, from design methodology to implementation choices and silicon results, for a reliable and cost effective testing procedure.

An adaptive synaptic array using Fowler\u2013Nordheim dynamic analog memory

In this paper we present an adaptive synaptic array that can be used to improve the energy-efficiency of training machine learning (ML) systems. The synaptic array comprises of an ensemble of analog memory elements, each of which is a micro-scale dynamical system in its own right, storing information in its temporal state trajectory. The state trajectories are then modulated by a system level learning algorithm such that the ensemble trajectory is guided towards the optimal solution. We show that the extrinsic energy required for state trajectory modulation can be matched to the dynamics of neural network learning which leads to a significant reduction in energy-dissipated for memory updates during ML training. Thus, the proposed synapse array could have significant implications in addressing the energy-efficiency imbalance between the training and the inference phases observed in artificial intelligence (AI) systems.

Advanced Nonvolatile Organic Optical Memory Using Self-Assembled Monolayers of Porphyrin-Fullerene Dyads.

Photo-switchable organic field-effect transistors (OFETs) represent an important platform for designing memory devices for a diverse array of products including security (brand-protection, copy-protection, keyless entry, etc.), credit cards, tickets, and multiple wearable organic electronics applications. Herein, we present a new concept by introducing self-assembled monolayers of donor–acceptor porphyrin–fullerene dyads as light-responsive triggers modulating the electrical characteristics of OFETs and thus pave the way to the development of advanced nonvolatile optical memory. The devices demonstrated wide memory windows, high programming speeds, and long retention times. Furthermore, we show a remarkable effect of the orientation of the fullerene–polymer dyads at the dielectric/semiconductor interface on the device behavior. In particular, the dyads anchored to the dielectric by the porphyrin part induced a reversible photoelectrical switching of OFETs, which is characteristic of flash memory elements. On the contrary, the devices utilizing the dyad anchored by the fullerene moiety demonstrated irreversible switching, thus operating as read-only memory (ROM). A mechanism explaining this behavior is proposed using theoretical DFT calculations. The results suggest the possibility of revisiting hundreds of known donor–acceptor dyads designed previously for artificial photosynthesis or other purposes as versatile optical triggers in advanced OFET-based multibit memory devices for emerging electronic applications.

Memory-assisted quantum accelerometer with multi-bandwidth

The accelerometer plays a crucial role in inertial navigation. The performance of conventional accelerometers such as lasers is usually limited by the sensing elements and shot noise limitation (SNL). Here, we propose an advanced development of an accelerometer based on atom–light quantum correlation, which is composed of a cold atomic ensemble, light beams, and an atomic vapor cell. The cold atomic ensemble, prepared in a magneto-optical trap and free-falling in a vacuum chamber, interacts with light beams to generate atom–light quantum correlation. The atomic vapor cell is used as both a memory element storing the correlated photons emitted from cold atoms and a bandwidth controller through the control of free evolution time. Instead of using a conventional sensing element, the proposed accelerometer employs interference between quantum-correlated atoms and light to measure acceleration. Sensitivity below SNL can be achieved due to atom–light quantum correlation, even in the presence of optical loss and atomic decoherence. Sensitivity can be achieved at the ng / Hz level, based on evaluation via practical experimental conditions. The present design has a number of significant advantages over conventional accelerometers such as SNL-broken sensitivity, broad bandwidth from a few hundred Hz to near MHz, and avoidance of the technical restrictions of conventional sensing elements.

Effects of retrieval-extinction training on internet gaming disorder.

Background and aimsInternet gaming disorder (IGD) leads to serious impairments in cognitive functions, and lacks of effective treatments. Cue-induced craving is a hallmark feature of this disease and is associated with addictive memory elements. Memory retrieval-extinction manipulations could interfere with addictive memories and attenuate addictive syndromes, which might be a promising intervention for IGD. The aims of this study were to explore the effect of a memory retrieval-extinction manipulation on gaming cue-induced craving and reward processing in individuals with IGD.MethodsA total of 49 individuals (mean age: 20.52 ± 1.58) with IGD underwent a memory retrieval-extinction training (RET) with a 10-min interval (R-10min-E, n = 24) or a RET with a 6-h interval (R-6h-E, n = 25) for two consecutive days. We assessed cue-induced craving pre- and post-RET, and at the 1- and 3-month follow-ups. The neural activities during reward processing were also assessed pre- and post-RET.ResultsCompared with the R-6h-E group, gaming cravings in individuals with IGD were significantly reduced after R-10min-E training at the 3-month follow-up (P < 0.05). Moreover, neural activities in the individuals with IGD were also altered after R-10min-E training, which was corroborated by enhanced reward processing, such as faster responses (P < 0.05) and stronger frontoparietal functional connectivity to monetary reward cues, while the R-6h-E training had no effects.Discussion and ConclusionsThe two-day R-10min-E training reduced addicts’ craving for Internet games, restored monetary reward processing in IGD individuals, and maintained long-term efficacy.

A New Meta-Heuristics Data Clustering Algorithm Based on Tabu Search and Adaptive Search Memory

Clustering is a popular data analysis and data mining problem. Symmetry can be considered as a pre-attentive feature, which can improve shapes and objects, as well as reconstruction and recognition. The symmetry-based clustering methods search for clusters that are symmetric with respect to their centers. Furthermore, the K-means (K-M) algorithm can be considered as one of the most common clustering methods. It can be operated more quickly in most conditions, as it is easily implemented. However, it is sensitively initialized and it can be easily trapped in local targets. The Tabu Search (TS) algorithm is a stochastic global optimization technique, while Adaptive Search Memory (ASM) is an important component of TS. ASM is a combination of different memory structures that save statistics about search space and gives TS needed heuristic data to explore search space economically. Thus, a new meta-heuristics algorithm called (MHTSASM) is proposed in this paper for data clustering, which is based on TS and K-M. It uses TS to make economic exploration for data with the help of ASM. It starts with a random initial solution. It obtains neighbors of the current solution called trial solutions and updates memory elements for each iteration. The intensification and diversification strategies are used to enhance the search process. The proposed MHTSASM algorithm performance is compared with multiple clustering techniques based on both optimization and meta-heuristics. The experimental results indicate the superiority of the MHTSASM algorithm compared with other multiple clustering algorithms.

Effect of laser-assisted heating and annealing on the crystal structure and magnetic properties of（Bi, &lt;i&gt;A&lt;/i&gt;）FeO&lt;sub&gt;3&lt;/sub&gt;（&lt;i&gt;A&lt;/i&gt;=Ca, Sr, Ba（alkaline earth metal）） thin films

High saturation magnetization is required for BiFeO3-based multiferroic（ferromagnetic/ferroelectric）thin films to apply magnetic writing element of Racetrack Memory which is a nextgeneration magnetic recording device. A newly introduced laser-assisted heating system was used to form high quality（Bi, A）FeO3（A=Ca, Sr, Ba（alkaline earth metal））thin films. The maximum substrate temperature was increased from 695 to about 858℃ by using this laserassisted heating system combining with lamp heating system of sputtering equipment. In the case of（Bi, Ca）FeO3 and（Bi, Sr）FeO3 with the Ca or Sr substitution concentration of 50～ 60 at％ fabricated by using the laser-assisted heating system, the crystallinity was improved, but oxygen vacancy could not be suppressed. As the result, saturation magnetization was not large. In the case of（Bi, Ba）FeO3 with the Ba substitution concentration of 50～60 at％ fabricated by using the laser-assisted heating system, oxygen vacancy could be suppressed. As the result, highest saturation magnetization of around 100 emu/cm3 was obtained in（Bi, Ba）FeO3 thin films.

Latter-Day Saint Roots in the American Forest: Joseph Smith’s Restoration Visions in Their Environmental Context

On 6 April 1830 Joseph Smith Jr. legally established what he claimed to be the restored Church of Jesus Christ that had existed previously during the New Testament times. This bold claim was bolstered by stories of angelic visitations in the hemlock–northern hardwood forest of New York and Pennsylvania by biblical and nonbiblical figures alike. In one of Smith’s supernatural encounters he claims that immediately prior to his theophany the Devil tried to intercede and prevent his communion with God. Thus, Smith and his followers have embraced a complex worldview concerning the nineteenth-century American forest, host to both the Divine and the Devil. The nineteenth-century American forest was complicated by its dangerous elements, its economic opportunities, and the sublime quality popularized in landscape paintings. Forests existed as environments that were equal in their ability to leave one desolate, well-provisioned, or inspired. Navigating these sometimes paradoxical views, Joseph Smith’s stories of otherworldly visitations in forest settings have resonated with many people seeking understanding in a confusing world. The founding story of The Church of Jesus Christ of Latter-day Saints and artistic depictions thereof demonstrate an evolving view of the American forest. The American forest is a malleable, liminal space in which Latter-day Saints have continually combined elements of faith and memory to create a unique faith tradition with roots in a transformative place in American society. This interdisciplinary paper examines the physical appearance of the hemlock–northern hardwood forest, the socioeconomic climate, shifting sentimental values, and the philosophical ideas popularized by transcendentalists and the Hudson River School of painters that provided the scaffolding for this resilient religious movement’s origin story.

Embryonic reactivation of FLOWERING LOCUS C by ABSCISIC ACID-INSENSITIVE 3 establishes the vernalization requirement in each Arabidopsis generation.

Many over-wintering plants grown in temperate climate acquire competence to flower upon prolonged cold exposure in winter, through vernalization. In Arabidopsis thaliana, prolonged cold exposure induces the silencing of the potent floral repressor FLOWERING LOCUS C (FLC) through repressive chromatin modifications by Polycomb proteins. This repression is maintained to enable flowering after return to warmth, but is reset during seed development. Here, we show that embryonic FLC reactivation occurs in two phases: resetting of cold-induced FLC silencing during embryogenesis and further FLC activation during embryo maturation. We found that the B3 transcription factor (TF) ABSCISIC ACID-INSENSITIVE 3 (ABI3) mediates both FLC resetting in embryogenesis and further activation of FLC expression in embryo maturation. ABI3 binds to the cis-acting cold memory element at FLC and recruits a scaffold protein with active chromatin modifiers to reset FLC chromatin into an active state in late embryogenesis. Moreover, in response to abscisic acid (ABA) accumulation during embryo maturation, ABI3, together with the basic leucine zipper TF ABI5, binds to an ABA-responsive cis-element to further activate FLC expression to high level. Therefore, we have uncovered the molecular circuitries underlying embryonic FLC reactivation following parental vernalization, which ensures that each generation must experience winter cold prior to flowering.