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Here, we report the results of strain-controlled spin-wave propagation regimes in a double-period multiferroic structure. It consists of an alligator-type magnonic crystal with a period of 250 μm and a piezoelectric layer, featuring a periodic counter-pin-type electrode system with a period of 125 μm. Employing microwave measurements, we acquired the transmission and dispersion of spin waves under various external electric field configurations applied to the piezoelectric layer. The formation of bandgaps in the magnon spectrum and the variation of the spin-wave transmission when altering the configurations of the external electric field are demonstrated. A finite element method reveals that the combination of the non-uniformity in the initial internal magnetic field of the magnonic crystal, which is caused by the presence of periodic alligator-type regions, together with elastic deformations, heightens the amplitude of the modulation of the internal magnetic field. Micromagnetic modeling has demonstrated that this modulation enhancement results in the variation of the spin-wave transmission at the frequency of the magnonic bandgap center of the magnonic crystal. The proposed design of the reconfigurable magnonic crystal creates a condition for the nucleation of the spin-wave bandgap, with further enhancement of the spin-wave reflection from the periodic grating induced by strain. We demonstrate the potential use of the proposed device as a multi-band NAND/NXOR spin-wave based logic gate. [ABSTRACT FROM AUTHOR]

As transistor footprint scales down to the sub-10 nm regime, the process development for advancing to further technology nodes has encountered slowdowns. Achieving greater functionality within a single chip requires concurrent development at the device, circuit, and system levels. Reconfigurable transistors possess the capability to transform into both n-type and p-type transistors dynamically during operation. This transistor-level reconfigurability enables field-programmable logic circuits with fewer components compared to conventional circuits. However, the reconfigurability requires additional polarity control gates in the transistor and potentially impairs the gain from a smaller footprint. In this paper, we demonstrate a 2D control-gate-free reconfigurable transistor based on direct modulation of out-of-plane conduction in an ambipolar MoTe2 channel. Asymmetric electrostatic gating at the source and drain contacts is employed in the MoTe2 transistor resulting in different Schottky barrier widths at the two contacts. Consequently, the ambipolar conduction is reduced to unipolar conduction, where the current flow direction determines the preferred carrier type and the transistor polarity. Temperature dependence of the transfer characteristics reveals the Schottky barrier-controlled conduction and confirms that the Schottky barrier widths at the top contact are effectively tuned by electrostatic gating. Without the complexity overhead from polarity control gates, control-gate-free reconfigurable transistors promise higher logic density and lower cost in future integrated circuits. [ABSTRACT FROM AUTHOR]

As fundamental scaling limits start to stifle the evolution of complementary metal–oxide–semiconductor transistor technology, interest in potential alternative computing platforms grows. One such alternative is wave-based computation. In this work, we propose a general string diagrammatic formalism for wave-based computation with phase encoding applicable to a wide range of emerging architectures and technologies, including quantum-dot cellular automata, single-electron circuits, spin torque majority gates, and DNA computing. We demonstrate its applicability for design, analysis, and simplification of Boolean logic circuits using the example of spin-wave circuits. [ABSTRACT FROM AUTHOR]

Exceptional points (EPs) are degeneracies of two or more eigenstates and eigenvalues in non-Hermitian systems, promising applications in optoelectronics. In particular, chiral state conversion can be achieved by dynamic encircling an EP to enable backward-scattering light isolation and asymmetric mode switching. However, critical bottlenecks have plagued most mainstream EP-based chiral mode converters, since they mainly use the traditional dual-coupled waveguide systems for parametric tuning as the essential part of the chiral mode converter, which induce mode mismatch, and bandwidth-limited EP encircling path and, therefore, cause deficiencies in crosstalk and bandwidth. To overcome this challenge, we propose a chiral mode converter adding customized subwavelength gratings (SWGs) in dual-coupled waveguide systems to enhance parametric tuning. Indeed, the SWG structure decreases crosstalk and enhances bandwidth by using its refractive index control characteristics to mitigate mode mismatch and weaken the wavelength correlation of the EP encircling path. The designed device has expanded the available working band, demonstrating favorable performance in both the optical communication band (1.26–1.675 μm) and 2 μm (1.85–2.05 μm) band. At the same time, the crosstalk reduces to below −20 and −13 dB, respectively, superior to most of the previously reported devices. Furthermore, the transmission efficiency remains above 90% in the full operating bands, which is at the advanced level as the reported optimal performance of chiral mode converters. This study paves the way for developing efficient chiral transmission devices (such as optical switches, isolators, and logic gates), inspiring fascinating opportunities in future optical communication and topological quantum computing technologies. [ABSTRACT FROM AUTHOR]

Valley degree of freedom has attracted great interest in the realization of topological edge states in acoustic systems owing to its rich valley-contrasting physics and great potential applications. However, the practice of valley acoustic topological insulators (ATIs) in designing tunable multifunctional devices without changing their structures still remains a great challenge. Here, we show that the antisymmetric and symmetric distribution nature of valley edge states in the valley ATIs with two different domain walls can be utilized to design tunable robust acoustic logic gates (ALGs). We experimentally demonstrate two types of tunable bifunctional ALGs (denoted as ALG-I and ALG-II), in which ALG-I is composed of a single domain wall, and ALG-II is constructed by a bent topological waveguide containing two domain walls. For ALG-I, the functions of logical inclusive OR and logical exclusive OR (denoted as OR and XOR, respectively) can be switched by actively tuning the phases of two input sound sources without changing the structure. For ALG-II, the logic functions OR and XOR can be implemented through the left and right incidences, respectively, of a pair of sound sources. Similarly, the switching of the logic functions OR and XOR on both sides of ALG-II can be realized by simply adjusting the phases of two sound sources. The designed ALGs have the advantages of simple structure, high robustness, as well as active tunability, leading to a wide range of potential applications in integrated acoustics, acoustic communications, and information processing. [ABSTRACT FROM AUTHOR]

Reversible computation has been proposed as a future paradigm for energy efficient computation, but so far few implementations have been realized in practice. Quantum circuits, running on quantum computers, are one construct known to be reversible. In this work, we provide a proof-of-principle of classical logical gates running on quantum technologies. In particular, we propose and realize experimentally, Toffoli and Half-Adder circuits suitable for classical computation, using radio frequency-controlled 171Yb+ ions in a macroscopic linear Paul-trap as qubits. We analyze the energy required to operate the logic gates, both theoretically and experimentally, with a focus on the control energy. We identify bottlenecks and possible improvements in future platforms for energetically efficient computation, e.g., trap chips with integrated antennas and cavity qed. Our experimentally verified energetic model also fills a gap in the literature of the energetics of quantum information and outlines the path for its detailed study, as well as its potential applications to classical computing. [ABSTRACT FROM AUTHOR]

Superconducting electronics are among the most promising alternatives to conventional CMOS technology, thanks to the ultra-fast speed and ultra-high energy efficiency of the superconducting devices. Having a cryogenic control processor is also a crucial requirement for scaling the existing quantum computers up to thousands of qubits. Despite showing outstanding speed and energy efficiency, Josephson junction-based circuits suffer from several challenges such as flux trapping leading to limited scalability, difficulty in driving high impedances, and so on. Three-terminal cryotron devices have been proposed to solve these issues, which can drive high impedances (> 100 k Ω) and are free from any flux trapping issue. In this work, we develop a reconfigurable logic circuit using a heater cryotron (hTron). In conventional approaches, the number of devices to perform a logic operation typically increases with the number of inputs. However, here, we demonstrate a single hTron device-based logic circuit that can be reconfigured to perform 1-input copy and NOT, 2-input AND and OR, and 3-input majority logic operations by choosing suitable biasing conditions. Consequently, we can perform any processing task with a much smaller number of devices. Also, since we can perform different logic operations with the same circuit (same layout), we can develop a camouflaged system where all the logic gates will have the same layout. Therefore, this proposed circuit will ensure enhanced hardware security against reverse engineering attacks. [ABSTRACT FROM AUTHOR]

In this experimental study, we explore the potential implementation of logic operations using the interference of propagating spin waves within a device composed of intersecting yttrium iron garnet waveguides with submicrometer width. Our investigation reveals the significant influence of finite-size effects on the performance of the microscopic devices. In particular, we observe that their efficiency depends on the wavelengths of the involved spin waves in relation to the size of the interference region and is reduced by multimode spin-wave propagation. These findings highlight crucial factors to be considered when designing magnonic nanodevices operating with short-wavelength spin waves, providing valuable insights for optimizing their performance in practical applications. [ABSTRACT FROM AUTHOR]

Self-powered flexible solar-blind photodetectors based on WSe2/β-Ga2O3 2D/3D van der Waals (vdW) heterojunctions were manufactured, which exhibit brilliant optoelectronic performances with a low dark current of 136 fA at 0 V, a I254nm/Idark ratio of 103, and rise (τr = 9 ms) and decay (τd = 18 ms) times. In a further step, a solar-blind communication system was fabricated with a good information transmission capability and low energy consumption. Furthermore, "AND" and "OR" optoelectronic logic gates have been realized, which can be applied to signal processing in the field of solar-blind communication. [ABSTRACT FROM AUTHOR]

Low-voltage electric-double-layer (EDL) p-channel Mg-doped CuI thin-film-transistors (TFTs) have been fabricated on glass substrates at low temperatures. Electrical properties of the solution-processed CuI TFTs with different Mg doping concentrations were investigated. It is observed that compared to undoped CuI TFTs and Mg0.1Cu0.9Ix TFTs, Mg0.05Cu0.95Ix TFTs exhibit an excellent current on/off ratio of 1.1 × 105, a steep subthreshold swing of 21.78 mV/dec, a higher saturation field-effect mobility of 0.95 cm2 V−1 s−1, and the threshold voltage of 1.81 V. The high specific capacitance of 4.7 μF/cm2 is obtained in solution-processed chitosan dielectrics; when it was used as the gate dielectric instead of traditional SiO2, the operating voltage of TFTs can be reduced to 2.5 V. It is noteworthy that the NAND logic function has been realized on the dual in-plane-gate structure of such Mg0.05Cu0.95Ix-based TFTs. Finally, the effects of laser (λ = 638 nm) and negative bias stress (NBS) were observed on Mg0.05Cu0.95Ix TFTs. The transfer curves of the TFT drifted positively as the power of the laser progressively increased; the OFF-state current gradually increased as the NBS time became longer. This paper provides an effective way to improve the performance of p-channel CuI TFTs and indicates that Mg0.05Cu0.95Ix as a promising p-type material for next-generation high-performance low-power-consumption logic circuit applications. [ABSTRACT FROM AUTHOR]

With the advantages of high speed, low energy consumption, and non-volatility, spin–orbit devices are promising to be used in the field of in-memory computing. However, for large-scale integration, a simpler field-free switching scheme needs to be further explored. Here, we prepared field-free spin–orbit devices based on the PtW alloy layer with competing spin currents. The preparation of such devices is friendly to integration, because there is no requirement of introducing additional processing technology. Only the traditional heavy-metal layer is needed to be replaced by an alloy layer with opposite spin Hall angles. A series of positive and negative pulsed current tests have shown a stable field-free magnetization switching in the Ta/PtW/Co/AlOx/Pt device. The programmable Boolean logic of NAND and NOR were performed in a single device by changing the initial magnetization state. In addition, a pair of devices were connected with always opposite magnetizations to implement the XNOR logic gate, which can be applied to perform the dot product operation in the binary neural network. Based on the spin XNOR gates, a three-layer binary neural network achieves 89% recognition accuracy of handwritten digits. Our findings pave the way to efficient in-memory computing applications. [ABSTRACT FROM AUTHOR]

The development of superconducting electronics based on nanocryotrons has been limited so far to few device circuits, in part due to the lack of standard and robust logic cells. Here, we introduce and experimentally demonstrate designs for a set of nanocryotron-based building blocks that can be configured and combined to implement memory and logic functions. The devices were fabricated by patterning a single superconducting layer of niobium nitride and measured in liquid helium on a wide range of operating points. The tests show 10 − 4 bit error rates with above ± 20 % margins up to 50 MHz and the possibility of operating under the effect of an out-of-plane 36 mT magnetic field, with ± 30 % margins at 10 MHz. Additionally, we designed and measured an equivalent delay-flip-flop made of two memory cells to show the possibility of combining multiple building blocks to make larger circuits. These blocks may constitute a solid foundation for the development of nanocryotron logic circuits and finite-state machines with potential applications in the integrated processing and control of superconducting nanowire single-photon detectors. [ABSTRACT FROM AUTHOR]

A two-dimensional hole gas (2DHG) induced by polarization charges at the GaN/AlGaN hetero-interface is attracting much attention because of its potential to develop p-channel transistors required for GaN complementary logic integrated circuits. This platform is compatible with commercial AlGaN/GaN n-channel electronics, but the performance of GaN p-channel transistors has been far behind. In this work, 2DHGs in GaN/AlGaN/GaN heterostructures grown by plasma-assisted molecular beam epitaxy have been investigated. The Al composition of the AlGaN barrier has been pushed as high as possible without obvious strain relaxation, and the record high 2DHG sheet density and conductivity on the GaN/AlGaN/GaN platform have been obtained. By adopting a parallel conduction model, a dependent relationship of the 2DHG density on temperature has been extracted. The temperature dependent Hall-effect results have demonstrated that the 2DHG density boosts by 75 times and 46 times at room temperature and 77 K, respectively, when the Al composition is pushed from 0.18 to 0.45 for the AlGaN barriers. The 2DHG sheet density reaches 3.6 × 1013 and 2.1 × 1013 cm−2 at room temperature and 77 K, respectively, and the lowest sheet resistance is 8.9 kΩ/□ at 77 K. Such a 2DHG is beneficial for fabrication of p-channel GaN transistors with lower on-resistance on the already-industrialized platform. [ABSTRACT FROM AUTHOR]

A fan-out circuit is a basic block for scaling up digital circuits for overcoming the limited driving capability of a single logic gate. It is particularly important for superconducting digital circuits as the driving power is typically weak for having high energy efficiency. Here, we design and fabricate a fan-out circuit for a superconducting nanowire cryotron (nTron) digital circuit. A classic splitter tree architecture is adopted. To transmit switching signal and avoid crosstalk among nTrons, we introduced an "R–L–R" interface circuit. Experimentally, a two-stage splitter tree of a fan-out number of four was demonstrated. Correct operation was observed with a minimum bit error rate (BER) of 10−6. The bias margin was 10% at BER of 10−4. The average time jitter was 82 ps. Moreover, crosstalk was not observed. Based on these results, we envision that the fan-out circuit can be used in future development of superconducting-nanowire-based circuits. [ABSTRACT FROM AUTHOR]

The logic gate is the basic unit of a digital circuit structure. The operation, memory, I/O, and other reading and writing functions of computer systems require logic circuits. Logic gates based on resistive memory can make existing integrated circuits denser, smaller, faster, and use fewer devices. In this paper, Al/polymethyl methacrylate (PMMA)/egg albumen (EA):Au nanoparticles/PMMA/Al multilayer biological resistive random access memory was prepared based on the natural biological material—egg albumen (EA). The device has bipolar switching behavior, a higher switching current ratio, a lower threshold voltage, and better stability. A circuit based on auxiliary logic is constructed using this device, and the logic functions of AND, OR, NOT, NAND, and NOR are realized. This device provides an effective potential solution for implementing high-performance electronic devices and large-scale integrated circuits. [ABSTRACT FROM AUTHOR]

Spintronic device based on spin–orbit torque (SOT) is a potential candidate for the next-generation memory and logic devices. Here, we report a SOT-based programmable multi-state logic-in-memory in a single unit. Multi-step magnetization switching behaviors can be achieved in the device with a stacking structure based on Pt/Co bilayers and an Al2O3 spacer layer by varying the thickness of Co and Pt layers. Moreover, five logic gates (NOR, OR, AND, NAND, and NOT) have also been realized by controlling the current and magnetic field. This multi-state logic-in-memory opens a simple and effective way for designing single-unit spintronic devices and extends the potential application of the SOT-based devices in brain-like computations. [ABSTRACT FROM AUTHOR]

Magnetic skyrmions are nanoscale topologically nontrivial spin texture that offer great promise as information carriers for the next-generation spintronic computing schemes. However, the current skyrmion-based logic gates require precise control of skyrmion collisions through clocked synchronizers, which leads to the complexity of logic implementation. To address this challenge, we propose a clockless skyrmion logic gate that can be implemented into large-scale computing networks without skyrmions synchronization. The clockless operations are achieved in a cross-shaped skyrmion track based on the skyrmion gating method with the aid of the voltage-controlled magnetic anisotropy gate. A complete set of Boolean operations and a cascaded full adder can be realized through the different combinations of inputs and interconnections of these logic gates. This computing paradigm paves the way for the design of a highly efficient and robust computing architecture using fully skyrmion-based logic devices. [ABSTRACT FROM AUTHOR]

The emergence of acoustic logic devices has attracted increasing attention owing to its great potential in logical operations and integrated acoustics. In recent years, various types of acoustic logic gates have successively been demonstrated based on artificial materials. However, simultaneous realization of acoustic logic devices with the characteristics of broad bandwidth and high robustness still poses a great challenge. To overcome this, we numerically design and experimentally demonstrate a multifunctional logic gate based on valley sonic crystals (VSCs). In a designed waveguide composed of two VSCs, a pair of valley edge states can be obtained in the domain wall. Additionally, we experimentally design a multifunctional logic gate composed of four VSCs. The logic functions OR and XOR with the fractional bandwidths of 0.24 and 0.19 can be realized at two output ports, which arises from both valley conservation and linear interference mechanisms. More importantly, we experimentally demonstrate the robustness of the logic gate by introducing a V-shaped defect, and the corresponding logic functions and their bandwidths created by the valley transport of edge states are almost immune to backscattering from the V-shaped defect. Compared with the previous acoustic logic gates, the proposed logic gate has the advantages of multifunctionality, broad bandwidth, and high robustness, which may have practical applications in advanced acoustic devices for computing and information processing. [ABSTRACT FROM AUTHOR]

Topological insulators are considered as one of the preferred materials for high-performance optoelectronic devices due to their small bulk bandgaps and ultra-high carrier mobility. However, the existence of their unique Dirac like surface states makes the corresponding optoelectronic devices to have high dark current, and the logic circuit cannot be turned off effectively. Opening the surface state gap by element doping is an effective means to achieve high performance of devices. Here, we design and prepare single crystal Bi2Se2.15S0.85 nanowires by a facile iodine-assisted chemical vapor transport method and a fabricated individual Bi2Se2.15S0.85 nanowire based photodetector. The devices exhibit remarkable photoresponse over the broadband wavelength ranging from ultraviolet C (275 nm) to near-infrared (1310 nm) with the low dark current of 10−12 A. They show superior optoelectrical properties with an ultrafast response speed of 170 ns, detectivity of 9.35 × 1011 Jones, a competitive responsivity of 1.31 A/W, and superb stability to keep great photoresponse for at least one year, which are superior to the reported photodetectors. Additionally, benefiting from the anisotropic crystal structure of Bi2Se2.15S0.85, the devices also display good polarization detection performance in a wide spectral range from 266 nm to 1064 nm with a dichroic ratio of 1.81 at 360 nm. [ABSTRACT FROM AUTHOR]

Heterojunctions and multi-gated structures facilitate the fabrication of high-performance and multifunctional transistors. Here, a WSe2/MoS2 heterojunction structure transistor with a back gate and two top gates is proposed. The back gate controls the carrier transport of the entire heterojunction channel, and the top gates independently control the carrier transports of MoS2 or WSe2 channels. The rectification direction of the heterojunction device could be reversed, and the rectification ratio could be modulated from 10−4 to 104 by changing the back-gate voltage. In addition, an evident negative-differential transconductance phenomenon with a current peak and a current valley are observed in the back-gate transfer characteristic curve, which results from the different control ability of the same gate voltage to the Fermi levels in MoS2 and WSe2. The current peak can be obviously modulated and eliminated by the MoS2 top gate, while the WSe2 top gate can control the position of the current valley from −8 to +12 V, which clearly supports the heterostructure energy band model. Moreover, the diversity of output states under multi-gate modulation makes applications in logic circuits possible. These results demonstrate the potential of this approach for the development of next-generation electronic functional devices. [ABSTRACT FROM AUTHOR]

Magnetic skyrmions are topological quasiparticles with nanoscale size and high mobility, which have potential applications in information storage and spintronic devices. Here, we computationally investigate the dynamics of isolated skyrmions in a ferromagnetic racetrack, where magnetic properties of the edges are enhanced and modified, forming a channel with lower magnetic anisotropy for skyrmion motion. It is found that the rectangular notch at the edge can have a pinning effect on the skyrmion and enrich the dynamics of the skyrmion. Based on the racetrack with modified edges and the notch, we design a racetrack that realizes the skyrmionic logic AND, OR, and NOT gates as well as the diode in the same magnetic racetrack. It is found that the driving current density could be much smaller than those used in previous designs of skyrmion-based logic gates. By slightly altering the shape of the racetrack, we also design the NAND and NOR gates. Finally, we study the feasibility of our design at finite temperatures. Our results may contribute to the design of nonvolatile spintronic devices with integrated multiple functions and ultra-low energy consumption. [ABSTRACT FROM AUTHOR]

We describe how a ladder emitter can implement a tunable quantum logic gate on photonic qubits encoded in the frequency basis. The ground-to-first excited state of the ladder emitter interacts with the control photon, and the first-to-second excited state transition interacts with the target photon. By controlling the relative detuning between the target photon and the first-to-second excited state transition of the ladder emitter, we enable any controlled-phase operation from 0 to π. We derive analytical formulas for the performance of the gate through the S-matrix formalism as well as describe the mechanism intuitively. This gate is deterministic, does not utilize any active control, and needs only a single ladder emitter, enabling low-footprint and more efficient decomposition of quantum circuits, especially the quantum Fourier transform. We suggest multiple potential systems for physical realization of our proposal, such as lanthanide ions embedded in Purcell-enhanced cavities. We expect these results to motivate further interest in photonic quantum information processing with designer emitters. [ABSTRACT FROM AUTHOR]

Enhancement-mode (E-mode) p-channel gallium nitride (GaN) field-effect transistors (p-FETs) are essential components for GaN-based complementary logic circuits. For the ease of integration with n-FETs, they could be fabricated on the commercial p-GaN gate high-electron-mobility-transistor (HEMT) platform, on which the two-dimensional electron gas at the AlGaN/GaN hetero-interface is completely depleted in as-grown epi-structures. However, under the gated region where p-GaN is recessed and depleted at thermal equilibrium, a parasitic electron channel (PEC) could appear at the AlGaN/GaN interface. This Letter reports experimental investigations on the PEC with specifically designed structures, confirming that the PEC does exist but imposes limited impacts on electrical characteristics of p-FETs. When connected with an external contact, the PEC could act as a back gate to modulate the overlaying p-channel. If isolated from external contacts, which is the case of p-FETs under normal operations, electrons in the PEC would redistribute under the active region of p-FETs in the horizontal direction (i.e., parallel to the surface) under different biases but are mostly confined near the AlGaN/GaN interface in the vertical direction (i.e., perpendicular to the surface). [ABSTRACT FROM AUTHOR]

Spin waves (SWs) have been considered a promising candidate for encoding information with lower power consumption. Here, we propose dual function SW logic gates, one unit cell with two synchronized logic operation functions, based on the electric field controlling of the SW propagation in the Fe film of a Fe / BaTiO 3 heterostructure by the motion of a magnetic anisotropy boundary. We show micromagnetic simulations to validate the and–or and nand–nor logic gates. Our research may find a path for simplifying integrated logic circuits using such dual function SW logic gates. [ABSTRACT FROM AUTHOR]

Magnonics, which employs spin-waves to transmit and process information, is a promising venue for low-power data processing. One of the major challenges is the local control of the spin-wave propagation path. Here, we introduce the concept of writable magnonics by taking advantage of the highly flexible reconfigurability and rewritability of artificial spin ice systems. Using micromagnetic simulations, we show that globally switchable spin-wave propagation and locally writable spin-wave nanochannels can be realized in a ferromagnetic thin film underlying an artificial pinwheel spin ice. The rewritable magnonics enabled by reconfigurable spin wave nanochannels provides a unique setting to design programmable magnonic circuits and logic devices for ultra-low power applications. [ABSTRACT FROM AUTHOR]

By means of local ion implantation, we investigated the influence of lateral interface on current induced magnetic switching by spin–orbit torque in a perpendicularly magnetized Pt/Co/Ta multilayer. The experimental results show that, in this system, the domain wall motion under electrical current can be affected by two mechanisms: symmetry breaking and current-driven Néel wall motion at the lateral interface. The dominant mechanism is symmetry breaking (current-driven Néel wall motion) at the large (small) current. Due to the competitive relationship of these two mechanisms, the non-hysteresis effect magnetic switching without an external magnetic field is obtained. Based on the non-hysteresis effect magnetic switching, we can realize AND and OR logic gates without resetting. [ABSTRACT FROM AUTHOR]

An on-chip superconducting microwave pulse generator (MPG), incorporating rapid single-flux-quantum (RSFQ) logic gates and passive radio frequency (RF) components, is an energy-efficient solution for controlling superconducting quantum bits (qubits). Traditional RSFQ MPG designs, however, suffer from a large footprint as multiple RF components (including impedance matching networks, filters, etc.) are separately implemented one after another. In this Letter, we propose a compact on-chip MPG by introducing an integrated RF module. Using a generalized filter synthesis technique, the integrated RF module combines the functionalities of impedance matching and bandpass filtering as a single inductor-capacitor (LC) lumped network. Plenty of circuit elements can, thus, be saved, and the resultant LC network is applicable to both real and complex terminal impedance cases. For validation, a superconducting MPG adopting a fourth-order, 5 GHz centered, 100 MHz bandwidth integrated RF module is designed and fabricated, whose correct operations are confirmed through both simulation and measurement. These results raise the availability of controlling large-scale quantum systems by low-power superconductor technology in the future. [ABSTRACT FROM AUTHOR]

Spin logics provide a shortcut toward logic-in-memory architectures. Here, using a T-type magnetic stack with a perpendicular magnetic layer, an in-plane layer, and a spacing layer in between, we can switch both the in-plane and perpendicular layers and independently control their magnetization without an external magnetic field. By initializing magnetization of the in-plane layer, we can further control chirality (clockwise and counterclockwise) of the current-dependence of perpendicular magnetization. Based on these properties and the majority gate theory, we experimentally construct five Boolean logic gates in a single device in the desired field-free condition, which steps forward to practical spin–orbit torque logics. [ABSTRACT FROM AUTHOR]

The outlook for producing useful practical devices within the paradigm of magnonics rests on our ability to emit, control, and detect coherent exchange spin waves on the nanoscale. Here, we argue that all these key functionalities can be delivered by chiral magnonic resonators—soft magnetic elements chirally coupled, via magneto–dipole interaction, to magnonic media nearby. Starting from the basic principles of chiral coupling, we outline how they could be used to construct devices and explore underpinning physics, ranging from basic logic gates to field programmable gate arrays, in-memory computing and artificial neural networks, and extending from one- to two- and three-dimensional architectures. [ABSTRACT FROM AUTHOR]

Nanographene exhibits manifold magnetic orders depending on its topology. The Clar's goblet, envisioned 50 years ago and synthesized recently, is an emblematic nanographene with an antiferromagnetic ground state induced by topological frustration. Inspired by the significant interest in the designer magnetic order of nanographene, we studied the tunable magnetic order in heteroatom-doped Clar's goblet. Interestingly, the antiferromagnetic to ferromagnetic transition is found in doped Clar's goblet by varying the doping positions. A large exchange-coupling strength of 77 meV is realized in a Clar's goblet doped by two nitrogen atoms. The spin directions and distribution at the connecting atoms determine the magnetic order and exchange-coupling strength. Moreover, the spin logic gate based on Clar's goblet can be converted from XOR (XAND) gate into OR (AND) gate by doping the outer units with nitrogen atoms. The heteroatom-doped nanographene with tunable magnetic order provides a platform for spintronic devices with controllable functions. [ABSTRACT FROM AUTHOR]

An induced nonlinear phase shift of spin waves excited in an yttrium iron garnet film waveguide has been studied. Experiments were performed with two microwave magnonic signals, being operating and pumping waves, co-propagated at different frequencies. The results show that a nonlinear phase shift up to 180° for the low-power operating wave is induced when increasing the pump-wave power. A theory describing the induced nonlinear phase shift is developed taking into account four-wave parametric coupling and nonlinear damping of two waves. The observed phenomenon paves the way to elaborate different types of nonlinear magnonic logic circuits. [ABSTRACT FROM AUTHOR]

The T-shaped spin conversion device consisting of ferromagnetic and spin Hall (or spin conversion) materials is an indispensable component in a new type of logic circuit called a magnetoelectric spin–orbit device. We examine the influence of the planar Hall effect (PHE) on the output signal in the T-shaped device. Angular dependences of decomposed even and odd components in the signal reveal that the PHE causes an even-symmetric component in the output signal because the magnetic moment continuously rotates clockwise (or counterclockwise). Thus, the PHE makes it challenging to detect odd magnetic field responses induced by the inverse spin Hall effect containing the zero-field magnetic state information. We can suppress the adverse effect by choosing a low anisotropic magnetoresistance ferromagnet. This study gives valuable information for designing the optimal T-shaped structure for the magnetoelectric logic device application. [ABSTRACT FROM AUTHOR]

Antiferromagnets are promising materials for future spintronic applications due to their unique properties including zero stray fields, robustness vs external magnetic fields, and ultrafast dynamics, which have attracted extensive interest in recent years. In this work, we investigate the dynamics of isolated skyrmions in an antiferromagnetic nanotrack with a voltage-gated region. It is found that the skyrmion can be jointly controlled by the driving current and the voltage-controlled magnetic anisotropy gradient. We further propose a design of logic computing gates based on the manipulation of antiferromagnetic skyrmions, which is numerically realized combining several interactions and phenomena, including the spin Hall effect, voltage-controlled magnetic anisotropy effect, skyrmion–skyrmion interaction, and skyrmion–edge interaction. The proposed logic gates can perform the basic Boolean operations of the logic AND, OR, NOT, NAND, and NOR gates. Our results may have a great impact on fundamental physics and be useful for designing future nonvolatile logic computing devices with ultra-low energy consumption and ultra-high storage density. [ABSTRACT FROM AUTHOR]

Possessing the noise-resilience feature, geometric phases have become important in robust quantum computation. Gates based on the Abelian and non-Abelian geometric phases have been experimentally demonstrated in different physical systems. However, previous proposals require cyclic evolution with a constant operation time even for small rotation angles, which set a limit to the gate operation time. Here, we experimentally realize noncyclic geometric gates, where the cyclic condition is removed and the operation time is proportional to the rotation angle. With the adiabatic process sped up by shortcut to adiabaticity, the fidelities of a noncyclic geometric gate characterized by randomized benchmarking are above 99.5%. Comparing with the dynamic scheme, we demonstrate the robustness of our gate against control instability in the experiment. Moreover, our results indicate that the noncyclic geometric gate with a smaller rotation angle corresponds to a shorter evolution time and higher fidelity. As small rotation angles are essential in the quantum algorithm, the superiority of noncyclic geometric gates makes them promising candidates in fast and robust quantum computation. [ABSTRACT FROM AUTHOR]

In this Letter, we present experimental data that demonstrate a spin wave interference detection using an inverse spin Hall effect (ISHE). Two coherent spin waves are excited in a yttrium-iron garnet waveguide by continuous microwave signals. The initial phase difference between the spin waves is controlled by the external phase shifter. The ISHE voltage is detected at a distance of 2 and 4 mm away from the spin wave generating antennas by an attached Pt layer. Experimental data show ISHE voltage oscillation as a function of the phase difference between the two interfering spin waves. This experiment demonstrates an intriguing possibility of using ISHE in a spin wave logic circuit converting a spin wave phase into an electric signal. [ABSTRACT FROM AUTHOR]

Magnetic skyrmions are exciting candidates for energy-efficient computing due to their nonvolatility, detectability, and mobility. A recent proposal within the paradigm of reversible computing enables large-scale circuits composed of directly cascaded skyrmion logic gates, but it is limited by the manufacturing difficulty and energy costs associated with the use of notches for skyrmion synchronization. To overcome these challenges, we, therefore, propose a skyrmion logic synchronized via modulation of voltage-controlled magnetic anisotropy (VCMA). In addition to demonstrating the principle of VCMA synchronization through micromagnetic simulations, we also quantify the impacts of current density, skyrmion velocity, and anisotropy barrier height on skyrmion motion. Further micromagnetic results demonstrate the feasibility of cascaded logic circuits in which VCMA synchronizers enable clocking and pipelining, illustrating a feasible pathway toward energy-efficient large-scale computing systems based on magnetic skyrmions. [ABSTRACT FROM AUTHOR]

To realize spin wave logic gates, programable phase inverters are essential. We image using phase-resolved Brillouin light scattering microscopy propagating spin waves in a one-dimensional magnonic crystal consisting of dipolarly coupled magnetic nanostripes. We demonstrate phase shifts upon a single nanostripe of opposed magnetization. Using micromagnetic simulations, we model our experimental finding in a wide parameter space of biasfields and wave vectors. We find that low-loss phase inversion is achieved, when the internal field of the oppositely magnetized nanostripe is tuned such that the latter supports a resonant standing spin wave mode with an odd quantization number at the given frequency. Our results are key for the realization of phase inverters with optimized signal transmission. [ABSTRACT FROM AUTHOR]

The realization of complete spin logic within a single nonvolatile memory cell is a promising approach toward next-generation low-power stateful logic circuits. In this work, we demonstrate that all 16 Boolean logic functions can be realized within a single four-state nonvolatile IrMn/Co/Ru/CoPt magnetic heterojunction, where controllable field-free spin–orbit torque switching of the perpendicularly magnetized CoPt alloy is obtained, relying on the interlayer exchange coupling and exchange bias effect. By assigning different values to four variables of the four-state memory, that is, the initial control current pulse, the initial control magnetic field, and the input electrical potential of two terminals, in sequentially three steps, the complete Boolean logic functions are realized, while the anomalous Hall voltage of the devices is considered as logic output. The coexistence of nonvolatile four-state memory and complete spin logic functions holds promising application for future computing systems beyond von Neumann architecture. [ABSTRACT FROM AUTHOR]

Programmable capability is highly demanded by adaptive multifunctional electronic and optoelectronic devices in various application fields, including logic circuits and data storage and sensing. The ideal platform to develop programmable devices is the van der Waals heterostructures (vdWHs) integrated by atomically thin layered two-dimensional transition metal dichalcogenides due to their broad distribution of bandgaps and highly tunable electrical and optical properties. Here, we demonstrated a gate-tunable MoTe2/WTe2 heterostructure based on semimetallic Td phase WTe2 and semiconducting 2H phase MoTe2. The developed devices concurrently exhibited a reversible and widely tunable rectification ratio ranging from ∼10−2 to 103, which is over 5 orders of magnitude. Correspondingly, we observed tunable self-excited photocurrent of the MoTe2/WTe2 vdWH, which can be switched between negative and positive values by gate bias. Moreover, the MoTe2/WTe2 vdWH showed an excellent photo-response with the maximum photoresponsivity up to 220 mA W−1 under gate bias with an amplitude of 40. Such widely tunable properties enable the usage of the MoTe2/WTe2 vdWH in multifunctional devices for photovoltaic and logic applications. [ABSTRACT FROM AUTHOR]

Phononic metamaterials enabled the realization of many acoustic components analogous to their electronic counterparts, such as transistors, logic gates, and calculators. A key component among these is the demultiplexer, a device that receives multiple signals and sorts them based on their frequencies into separate channels. Previous experimental realizations of acoustic and elastic multiplexers have employed plates with pillars or holes to demultiplex frequencies. However, existing realizations are confined to two dimensions, which can limit potential acoustic or elastic circuit design. Here, we show an experimental realization of a three-dimensional, four channel phononic demultiplexer. Our design methodology is based on bundles of pass-bands within a large bandgap that can easily be tuned for multi-channel frequency demultiplexing. The proposed design can be utilized in acoustic and elastic information processing, nondestructive evaluation, and communication applications, among others. [ABSTRACT FROM AUTHOR]

The ability to engineer the interactions in assemblies of nanoscale magnets is central to the development of artificial spin systems and spintronic technologies. Following the emergence of the Dzyaloshinskii–Moriya interaction (DMI) in thin film magnetism, new routes have been opened to couple the nanomagnets via strong chiral interactions, which is complementary to the established dipolar and exchange coupling mechanisms. In this Perspective, we review recent progress in the engineering of synthetic magnets coupled by the interlayer and intralayer DMI. We show how multilayer chiral magnetic structures and two-dimensional synthetic antiferromagnets, skyrmions, and artificial spin systems can be realized by simultaneous control of the DMI and magnetic anisotropy. In addition, we show that, with the combination of DMI and current-induced spin–orbit torques, field-free switching of synthetic magnetic elements is obtained as well as all-electric domain wall logic circuits. [ABSTRACT FROM AUTHOR]

Organic electrochemical transistors (OECTs) have shown great promise in a variety of applications ranging from digital logic circuits to biosensors and artificial synapses for neuromorphic computing. The working mechanism of OECTs relies on the mixed transport of ionic and electronic charge carriers, extending throughout the bulk of the organic channel. This attribute renders OECTs fundamentally different from conventional field effect transistors and endows them with unique features, including large gate-to-channel capacitance, low operating voltage, and high transconductance. Owing to the complexity of the mixed ion-electron coupling and transport processes, the OECT device physics is sophisticated and yet to be fully unraveled. Here, we give an account of the one- and two-dimensional drift-diffusion models that have been developed to describe the mixed transport of ions and electrons by finite-element methods and identify key device parameters to be tuned for the next developments in the field. [ABSTRACT FROM AUTHOR]

A spin–orbit torque-based logic device that combines the Dzyaloshinskii–Moriya interaction and asymmetric shape anisotropy is proposed in this paper. Through magnetization switching of the magnetic tunnel junction (MTJ), four distinct input cases are determined to perform all of the 16 basic Boolean functions by a single magnetic tunnel junction (MTJ). With various combinations of the tilted angle of the MTJ and the value of current density, a single MTJ can serve as a reconfigurable logic gate. [ABSTRACT FROM AUTHOR]

Conventional silicon-based devices are approaching the scaling limits toward super miniaturization, where the quantum size effect naturally emerges with increasing importance. Exploring the quantum size effect may provide additional functionality and alternative architectures for information processing and computation. Scanning tunneling microscopy/spectroscopy is an ideal tool to explore such an opportunity as it can construct the devices in an atom-by-atom fashion and investigate their morphologies and properties down to the atomic level. Utilizing nanocorrals as examples, the quantum size effect is demonstrated to possess the great capability in guiding the adatom diffusion and the self-assembly, controlling the statistical fluctuation, tuning the Kondo temperature, etc. Besides these fundamentals, it also shows strong potential in logic operations as the basic logic gates are constructed. [ABSTRACT FROM AUTHOR]

Adiabatic quantum-flux-parametron (AQFP) logic is a highly energy-efficient superconductor logic family. Traditionally, AQFP circuits have relied on the four-phase clocking scheme, which uses a pair of ac current sources with a 90° phase difference. The operation of each logic gate thus takes a quarter clock cycle, leading to a relatively long latency for some applications. In this Letter, we propose a low-latency clocking scheme for AQFP logic based on microwave power dividers (PDs). The whole circuit is powered by a single excitation current, which is equally split for each logic stage by a serial-type PD. As a result, the latency between adjacent logic stages is determined by the transmission line length (propagation delay) inside the PD, which can be much shorter than a quarter clock cycle. Note that the low-latency performance is independent of the horizontal length of the AQFP circuit, and thus, the proposed clocking scheme is applicable to large-scale designs where a large number of gates are horizontally placed in a single stage. For validation, several numerical simulations are conducted and a six-stage AQFP test circuit is demonstrated using the proposed power-dividing clocking scheme (with a designed latency of 20 ps per gate) at a temperature of 4.2 K. [ABSTRACT FROM AUTHOR]

Integrated optical computing has the potential to enhance the computation abilities in terms of computing speed and power consumption during the post-Moore's law era. As one of the widely investigated approaches, electro-optic logic uses electro-optic switches as the building blocks to achieve complex functions. In this paper, we propose and experimentally demonstrate a multioperand electro-optic logic gate that contains multiple active regions in a single gate to further increase the versatility of gates. Thus, one gate can be controlled by several electrical inputs simultaneously. The ability of multioperand logic gates is thoroughly explored. The detailed comparison shows that the proposed gate can largely improve the circuit performance in terms of the area, latency, power, and insertion loss. We believe the multioperand logic gate has the potential to contribute to a more compact and power-efficient integrated optical computing system. [ABSTRACT FROM AUTHOR]

In this letter, we demonstrated improved resistive switching (RS) characteristics for a complementary metal-oxide-semiconductor compatible Ni/Ti/Al2O3/SiO2/Si device structure. The robust SiO2 layer deposited by the additional low-pressure chemical vapor deposition process can improve the RS characteristics such as the endurance cycle, current level, and on/off ratio. Moreover, the multilevel capability is enhanced in the bilayer structure; the larger the reset stop voltage, the greater the on/off ratio demonstrated. Furthermore, for practical RS operation, several resistance states were obtained by adjusting the pulse amplitude. This property is desirable for highly integrated nonvolatile memory applications. [ABSTRACT FROM AUTHOR]

A redox reaction submerged by a high current magnitude is impressively observed in a Fe2O3 solid electrolyte-based resistive memory device at room temperature. Oxygen vacancy migration, Ag atom redox, phase-induced grain boundary, and water molecule interplay with the oxygen vacancy are responsible for the submerged redox behaviors. The observation of the submerged redox behavior in the Fe2O3 phase change process gives an insight into the evolution of memristors. [ABSTRACT FROM AUTHOR]

By sandwiching a CoFeB ferromagnetic layer between Ta and Pt heavy metals with an opposite spin Hall angle, spin currents of the same polarity are transmitted from both interfaces of the Ta/CoFeB/Pt trilayer to the CoFeB layer simultaneously. Here, we investigated the spin-orbit torque, magnetization dynamics, and interface spin transmission efficiency of the trilayer heterostructure by spin-torque ferromagnetic resonance. A large effective spin Hall angle, substantially larger than both Ta and Pt, was obtained in the Ta/CoFeB/Pt stack. The thickness-dependence study showed that with the reducing of CoFeB thickness, Gilbert damping enhances by spin pumping and spin Hall angle increases by the spin Hall effect and the Rashba effect. Furthermore, the spin transparency derived from effective spin mixing conductance was 0.63 ± 0.07 and 0.48 ± 0.02 at the CoFeB/Pt and Ta/CoFeB interfaces, respectively. Hence, the spin Hall angle could be further enhanced by improving the spin transmission efficiency at the interface. Our method of increasing spin-orbit torque through stack engineering would have potential applications in domain wall racetrack memory, logic gates, and magnetic tunnel junctions. [ABSTRACT FROM AUTHOR]

Here, hydrogenated diamond (H-diamond) NOR logic circuits composed of two p-type enhancement-mode (E-mode) metal-oxide-semiconductor field-effect-transistors (MOSFETs) and a load resistor are fabricated and characterized. The fabrication process and the annealing effect on the electrical properties of the NOR logic circuit are demonstrated. There are distinct logical characteristics for the as-received and 300 °C annealed NOR logic circuits. When one or both input voltages for the E-mode MOSFETs are −10.0 V and “high” signals, output voltages respond 0 V and “low” signals. Instead, when both input voltages are 0 V and “low” signals, output voltage responds −10.0 V and a “high” signal. After annealing at 400 °C, the NOR logical characteristics are damaged, which is possibly attributed to the degradation of the H-diamond MOSFETs. [ABSTRACT FROM AUTHOR]