This work developed a dimpled TiO2 ceramic with abundant oxygen vacancies for efficient solar-driven interfacial evaporation. Multiscale porous structures and surface dimple morphologies were constructed on the TiO2 ceramic via titanium powder coating, followed by sequential vacuum heat treatment and hydrothermal processing, with oxygen vacancies further enhancing the optical absorption and photothermal conversion capabilities. Systematic experiments revealed that the optimized sample achieved a solar-spectrum absorption of 93.78%, a photothermal conversion efficiency of 73.3%, an evaporation rate of 1.63 kg & centerdot;m-2 & centerdot;h-1, and a reduced evaporation enthalpy of 1.81 MJ & centerdot;kg- 1, yielding an overall solar-to-steam efficiency of approximately 75%. The study demonstrates that the dimple architecture synergistically promotes light harvesting, facilitates heat localization, and creates low-enthalpy evaporation pathways via capillary effects, thereby offering a promising strategy for developing high-efficiency, durable solar desalination materials.

Bismuth silicate (Bi4Si3O12, BSO) crystals, due to their high stopping power, fast decay, and low raw material cost, are expected to be applied in future high-energy physics (HEP) experiments. However, the high-quality and large crystal growth have restricted its practical HEP applications as a cost-effective scintillator. In this study, BSO crystals with dimensions up to 22.6 & times; 22.6 & times; 369 mm(3) (SIC-BSO-369) and 18.6 & times; 18.6 & times; 259 mm(3) (SIC-BSO-259) were successfully grown. These are the longest BSO single crystals reported to date. Their scintillation properties were measured, including transmittance, photoluminescence (PL), X-ray excited emission, energy resolution (ER), and light response uniformity (LRU). The results show that the SIC-BSO-259 crystal exhibits a high longitudinal transmittance (78.32%@480 nm) close to the theoretical limit value, demonstrating excellent optical quality. Due to internal scattering, the longitudinal transmittance of the SIC-BSO-369 crystal is 45.27% at 480 nm. The average ER of the SIC-BSO-259 and SIC-BSO-369 for 662 keV gamma rays are 27.2% and 29.0%, respectively. And their average absolute light output (LO) are 776 and 735 ph/MeV, respectively. The optimal LRU (delta value) of SIC-BSO-259 is-0.52% +/- 0.5% with a combination of all polished surfaces and ESR as high-reflector material, while for SIC-BSO-369 is 1.41% +/- 1.8% with Tyvek wrapped.

Superconducting quantum interference devices (SQUIDs) based on nanobridge junctions (NBJs) are promising platforms for highly sensitive magnetic detection. The SQUID performance is influenced by the non-sinusoidal current-phase relation (CPR) of NBJs. In this work, we measured the flux modulation of 10 asymmetric Nb SQUIDs based on three-dimensional NBJs, along with the CPR response in each device, which is mainly determined by the junction with the smaller critical current. By studying the CPR parameters (skewness Δθ, critical current Ic1, and effective junction inductance Lj), together with the SQUID modulation characteristics (voltage modulation amplitude ΔIcRn and current modulation ratio ΔIc/2Ic1), we found that as Ic1 increases from 0.6 μA to 6.6 μA and Lj correspondingly decreases from 106 pH to 70 pH, the CPR skewness Δθ increases from 0.2 rad to 1.5 rad. Over this range, ΔIc/2Ic1 decreases from 1.2 to 0.5, while ΔIcRn increases from about 0.06 mV to 0.22 mV. More specifically, ΔIcRn increases while ΔIc/2Ic1 decreases with increasing Ic1, whereas both quantities decrease with increasing Lj. These results reveal a trade-off between intrinsic SQUID response and tolerance to readout noise, suggesting that improved performance can be achieved by engineering NBJs with increased Ic1 and smaller Lj.

Abstract Employing superconducting memory to construct neuromorphic hardware offers a promising route to low-energy and high-speed computation while mitigating the data-transfer bottleneck between superconducting functional modules inherent to the conventional von Neumann architecture. In this work, we develop an in-memory computing architecture based on a superconducting multi-fluxon storage device made of nanoscale JJs. It is capable of implementing fundamental neural network operations, and supports 4 discrete synaptic weight storage and probabilistic weighted computation of inputs, achieving clear classification performance and 100% accuracy on a9-pixell image recognition task. By increasing the discretization levels of synaptic weights, the architecture is expected to handle more complex information-processing tasks, such as recognition of the Modified National Institute of Standard and Technology handwritten digit dataset. These results highlight the potential of superconducting memory devices as scalable and powerful building blocks for emerging computing architectures toward general artificial intelligence.

Brain-inspired computing paradigms offer a more energy efficient approach for artificial intelligence. The spike-timing-dependent plasticity of biological neural synapses reveals the potential learning mechanisms of the brain. This work proposes a synaptic circuit design based on superconducting Josephson junctions. The circuit achieved the functions that include spike sequence judgment of pre-synaptic and post-synaptic neurons, weight storage, and probabilistic-coded weight calculation of spike counts. Simulations show that the combined functions of each part of the circuit can emulate the spike-timing-dependent plasticity of biological neural synapses. When integrated with existing superconducting single-flux-quantum circuits, it successfully models the “winner-takes-all” behavior of the biological brain. Embedding this synaptic circuit into superconducting integrated circuits could be an important step towards the future development of brain-inspired superconducting computational systems.

Abrikosov vortices trapped in superconducting circuits can reduce their operation margin and, in some cases, even lead to failure. Moats have been introduced to reduce the impact of Abrikosov vortices by providing a favorable location for trapping them at a distance from the circuit. However, the distribution mechanism of vortices near moats driven by applied magnetic fields and currents remains unclear. In this study, we used multiple moats to construct square-shaped areas in the niobium (Nb) thin film and employed magnetic force microscopy to observe the distribution of vortices induced by applied magnetic fields and currents near these areas. The moats effectively prevented vortices from entering the square-shaped area, particularly when the spacing between two moats was <550 nm. Furthermore, we discovered that the edges of moats generated new vortices with polarities opposite to those entering from both the edges of the Nb film under applied current. These vortices attracted each other and annihilated in pairs. These findings provide more insights into designing the layouts of superconducting integrated circuits.

Phase Change Memory (PCM) technology, particularly utilizing GeTe-based materials, has emerged as a compelling alternative to traditional nonvolatile memory systems, offering significant advancements in speed, scalability, and endurance. This review provides an in-depth analysis of recent developments in GeTe PCM, focusing on the challenges and breakthroughs that have characterized its evolution. Key aspects of resistance drift, material aging, and crystallization dynamics were explored, with special attention to the fundamental mechanisms, including β-relaxation and the Fragile-to-Strong Transition in supercooled liquids, along with Peierls distortions. Innovations in material engineering, such as alloying and nanoconfinement, have been discussed for their roles in enhancing device performance and reliability. Furthermore, this review examines the impact of advanced fabrication techniques and novel device architectures on the practical applications of PCM. By integrating these technological advancements with a theoretical understanding of the material properties, this review highlights the transformative potential of GeTe PCM across various applications, setting the stage for future research directions aimed at fully realizing the capabilities of this promising memory technology.

TaN films were employed as the barrier layer, and by adjusting the nitrogen content f N2 during the deposition of the TaN barrier layer, underdamped and overdamped Josephson junctions were fabricated using NbN/TaN/NbN trilayers. As f N2 was varied from 60% to 100%, the optical band gap of the TaN film exhibited a non-monotonic trend, peaking at f N2 of 80%, where the NbN/TaN/NbN trilayer achieved its best epitaxial quality. For f N2 ranging from 60% to 90%, the NbN/TaN/NbN junction exhibited typical tunnel junction characteristics, also with peak performance at f N2 = 80%: the energy gap voltage V g was 5.5 mV, the characteristic voltage I c R n reached 4.5 mV, and the critical current density J c could be finely tuned between 40 kA cm −2 to 0.6 kA cm −2 by adjusting the barrier thickness from 2.3 nm to 3.3 nm. When f N2 increased to 100%, the counter NbN electrode evolved into a polycrystalline structure. Concurrently, the resistance of the NbN/TaN/NbN junction dropped sharply, accompanied by the vanishing of V g in the I – V curve and a marked surge in J c , signaling a shift from superconductor–insulator–superconductor to superconductor–normal metal–superconductor junction. At f N2 of 80%, the average barrier height ϕ was roughly 0.04 eV, substantially lower than that of AlN. This lower ϕ suggests that the same J c can be maintained even with a thicker TaN barrier, thereby improving the process stability and reproducibility of NbN junctions at high J c .

The nanobridge junctions (NBJs) allow the miniaturization of the Superconducting Quantum Interference Device (SQUID) and improve the spatial resolution of scanning SQUID microscopy. However, the SQUID loop diameter imposed a fundamental limit on the resolution. In this work, we proposed a single niobium-nitride-based three-dimensional nanobridge junction (NbN-3D-NBJ) alternative to the nanoSQUID for high-resolution magnetic imaging. The critical current of an NbN-3D-NBJ showed a nearly monotonic dependence on the external magnetic field, enabling nanoscale mapping of the magnetic field distribution by measuring the junction's critical current with an intrinsic noise level of 100 nT/√Hz. Using a NbN-3D-NBJ probe, we successfully imaged an Abrikosov vortex in a niobium film with a minimal full width at half maxima (FWHM) of 0.53 μm, constrained by the distance from the junction to the probe tip edge. Furthermore, we resolved 80 nm spacings between the superconducting nanowires utilizing a second probe with an optimized junction-to-tip distance. Thus, the single 3D NbN NBJ probe has been demonstrated as an effective approach for magnetic imaging with ultrahigh spatial resolution.

Superconducting memory cells that use flux quanta as their storage medium can achieve ultra-fast access times with ultra-low power consumption. However, the data signal generated by a flux quantum memory (FQM) cell is usually too weak and too fast to be measured directly. Here, we present a method to characterize the real-time operation of an FQM cell. The storage loop of the FQM cell, configured with a Nb/NbNX/Nb Josephson junction, was proven the capability to store multiple flux quanta. The readout was demonstrated by a superconducting quantum interference device composed of underdamped Nb/Al-AlOX/Nb Josephson junctions. The writing and reading operations were achieved by a short pulse ranging from 0.1 ns to 2.5 ns, and a constant bit error rate of similar to 2.46% was measured for the fabricated FQM cell. The method presented here can be used to study real-time operation of an FQM cell in a direct manner.

AbstractWith the goal of achieving carbon neutrality, active distribution networks (DNs) with a high proportion of photovoltaics (PVs) are facing challenges in maintaining voltage stability and low‐carbon operation. Energy storage systems (ESSs), which have the ability to store and transfer energy temporarily, can be used as effective measures to enhance the capacity of consuming PVs and reduce carbon emissions in DNs. However, existing low‐carbon dispatch strategies for multiple sources, storages and loads fail to consider voltage violations, while the temporal carbon emission intensity of the upper‐level power grid is also often overlooked, which is an important factor that affects the dispatch strategy. Therefore, a two‐stage self‐adaptive dispatch strategy of ESSs that considers the temporal characteristics of slack nodal carbon emission intensity to minimise carbon emissions while maintaining voltage stability in DNs with high access to PVs is proposed. First, the framework of the proposed two‐stage self‐adaptive dispatch strategy of ESSs is established by taking into account the effects of ESSs on adjusting voltages and reducing carbon emissions, respectively, with the two‐stage switch principle of two operation modes being determined. On this basis, an optimization dispatch model is established to improve voltages and carbon emissions, and the optimal day‐ahead dispatch strategy of ESSs can be obtained by solving the model using genetic algorithm. Case studies of the modified 10 kV IEEE 33‐node DN and IEEE 123‐node DN verify the feasibility and superiority of the proposed two‐stage self‐adaptive security and low‐carbon day‐ahead dispatch strategy for ESSs, showing that the voltage stabilisation and lower carbon emissions of DNs are both improved.

Traditional simulation of complex mechanical systems relies on numerical solvers of Partial Differential Equations (PDEs), e.g., using the Finite Element Method (FEM). The FEM solvers frequently suffer from intensive computation cost and high running time. Recent graph neural network (GNN)-based simulation models can improve running time meanwhile with acceptable accuracy. Unfortunately, they are hard to tailor GNNs for complex mechanical systems, including such disadvantages as ineffective representation and inefficient message propagation (MP). To tackle these issues, in this paper, with the proposed Up-sampling-only and Adaptive MP techniques, we develop a novel hierarchical Mesh Graph Network, namely UA-MGN, for efficient and effective mechanical simulation. Evaluation on two synthetic and one real datasets demonstrates the superiority of the UA-MGN. For example, on the Beam dataset, compared to the state-of-the-art MS-MGN, UA-MGN leads to 40.99 but using only 43.48 operations (FLOPs).

Rapid Single Flux Quantum (RSFQ) circuits are promising for energy-efficient and high-frequency digital applications. Energy consumption could be reduced effectively when RSFQ circuits operate at higher temperatures. We developed a fabrication process for all-NbN RSFQ circuits based on NbN/AlN/NbN Josephson junctions on single-crystal MgO substrates with the NbN ground layer on the top. The electrical properties of NbN junctions and NbN inductance were measured in the temperature range from 4.2 to 14 K. The NbN junction parameters decreased with an increase in temperature. The value of NbN inductance increased with an increase in temperature. The all-NbN Josephson Transmission Line (JTL) was designed, fabricated, and tested in the temperature range of 10 K. The result showed that the NbN-based JTL can work stable at 10 K. The margins were measured near 10 K.

In this paper, we presented a quantitative refocused INEPT (Refocused Insensitive Nuclei Enhanced by Polarization Transfer) method based on simulated annealing optimization, which utilizes the optimized polarization transfer and refocus delay set to yield nearly uniform enhancement for CH, CH2 and CH3 groups. The 180° composite pulses are applied in 13C channel to overcome the inhomogeneity of B1 field and the offset effect to improve the measurement reliability. Simulated annealing optimization is further applied to achieve quantitative spectral editing of refocused INEPT. The above methods were validated using model compounds such as artemisinin and simvastatin, and the relative standard deviations of the quantitative integrals with Case I delay set were 1.6% and 3.3%, respectively. As an application of the proposed method, major fatty acid compositions in soybean oils were determined using quantitative refocused INEPT, and the results were consistent with those determined by conventional quantitative 13C NMR, while the measurement time was significantly reduced. The quantitative refocused INEPT method is particularly attractive for rapid, accurate detection of complex systems such as petroleum and polymers.

2D magnetic semiconductors exhibit great potential for next-generation spintronics, but realizing their full capabilities has been hindered by the low Curie temperatures (T-c) below 50 K observed in current materials. Here, a new mechanism to substantially enhance the T-c of 2D semiconducting materials through incorporating both in-plane and out-of-plane superexchange interactions enabled by structural design is demonstrated. Specifically, monolayer Cr2Se3 is synthesized with a five-layer Se-Cr-Se-Cr-Se atomic structure using molecular beam epitaxy (MBE). This unique structure not only possesses optimized in-plane superexchange interaction but also incorporates out-of-plane Cr-Se-Cr couplings. Scanning tunneling spectroscopy (STS) and angular-resolved photoemission spectroscopy (ARPES) confirm its semiconducting nature. Remarkably, the ferromagnetic phase transition observed by ARPES and Magnetic Force Microscopy (MFM) indicated that its T-c is up to 230 K. This not only establishes a new record for T-c in 2D ferromagnetic semiconductor materials but also introduces a novel approach to modulating materials' properties by manipulating the vertical dimension in 2D materials.

We report on the electrical properties of NbN/TaN/NbN Josephson junctions grown on thermally oxidized silicon substrates, along with the design and fabrication of superconducting single-flux-quantum (SFQ) circuits based on these NbN superconductor/normal metal/superconductor (SNS) junctions. The critical current density (Jc) of the junctions was found to be relatively sensitive to the barrier thickness, decreasing from 108.0 +/- 8.1 kA cm-2 for a 15 nm barrier to 12.8 +/- 1.9 kA cm-2 for a 30 nm barrier. For a Jc of approximately 24.5 +/- 2.1 kA cm-2 and a barrier thickness of 25 nm, the NbN SNS junctions are self-shunted and exhibit nonhysteretic current-voltage (I-V) characteristics. Especially for junctions with diameter (phi) ranging from 0.8 to 1.6 mu m, their critical current (Ic) falls within the range of 110-450 mu A, making them suitable for SFQ circuits. By considering the impact of excess current and incorporating it as an additional term in the conventional resistively and capacitively shunted junction model, the I-V curves of NbN SNS junctions can be precisely described, successfully minimizing the deviation between simulations and test results. The DC-SFQ and SFQ-DC interface circuits can both operate normally, and the bias margins of cell circuits such as Josephson transmission line, confluence buffer, D flip-flop, and splitter are greater than 40%. Compared to Nb superconductor/insulator/superconductor junctions, their self-shunting characteristics and relatively thick 25 nm barriers can also enhance the integration of circuits and increase the yield to complex circuits.

Resistively shunted Nb/Al-AlO x /Nb Josephson junctions have been widely used in large-scale superconducting electronics such as the single-flux quantum circuit. The critical current primarily determines the working margin of the circuit. The distribution of vortices in the niobium film around superconducting devices is also commonly suspected to degrade the performance of devices. Unfortunately, most studies on Nb/Al-AlO x /Nb Josephson junctions only present electric transport measurements. Using a magnetic force microscope, we observed the static distribution of the vortices around the junction after sweeping the current–voltage curves of the junction in-situ. The measurements showed that the distribution density of vortices affected the critical current of the junction. Furthermore, we observed an aggregation of vortices arising from the Joule heat generated by the shunt resistor. This caused an irreversible decrease in the junction’s critical current.

The nanobridge junction (NBJ) is a type of Josephson junction that is advantageous for the miniaturization of superconducting circuits. However, the current-phase relation (CPR) of the NBJ usually deviates from a sinusoidal function, which has been explained by a simplified model with correlation only to its effective length. Here, we investigated both measured and calculated CPRs of niobium NBJs of a cuboidal shape with a three-dimensional bank structure. From a sine-wave to a sawtooth-like form, we showed that deviated CPRs of NBJs can be described quantitatively by its skewness Δθ. Furthermore, the measured dependence of Δθ on the critical current I0 from 108 NBJs turned out to be consistent with the calculated dependence derived from the change in geometric dimensions. This suggested that the CPRs of NBJs can be tuned by their geometric dimensions. In addition, the calculated scaling behavior of Δθ versus I0 in 3D space was provided for the future design of superconducting circuits of a high integration level by using niobium NBJs.

Niobium nitride (NbN) is an important material for superconducting electronics because of its relatively high transition temperature in comparison to other conventional superconductors. Recent advances in the use of gas field focused ion beams for material modification motivate directly written NbN electronics. In this work, we study the electrical transport properties of ultra-thin film NbN microbridges irradiated with a focused helium ion beam. Twenty 4- $\mu$ m wide strips were structured into an NbN thin film and irradiated with a helium ion microscope with ion fluences ranging from $1 \times 10^{18}$ He $^+/$ cm $^{2}$ to $3 \times 10^{18}$ He $^+/$ cm $^{2}$ . We report the temperature and magnetic field dependence of the transport properties. At a higher dose of $1 \times 10^{20}$ He $^+$ , the irradiation reduces the critical temperature of a narrow region resulting in a planar superconductor-reduced $T_{c}$ superconductor-superconductor (SS'S) Josephson junctions. This establishes that NbN can be modified in this manner for nanoelectronics, opening up possibilities for superconducting logic circuits and other higher-speed and high-temperature applications.