Browse Articles

Revealing space-charge capacitance in multi-layer dielectrics with Sb2O3/MoS2/SiO2

Antimony trioxide (Sb2O3) has recently attracted attention as a top-gate dielectric for two-dimensional transition metal dichalcogenide materials due to its high permittivity and van der Waals gap, which contribute to minimal mobility degradation. In this study, the MIS dielectric behavior of Au/Al/Sb2O3/SiO2/P++Si capacitors was investigated under different alternating-current (AC) frequencies and direct-current (DC) bias voltages. The results demonstrated an exponential dependence of capacitance on the DC bias voltage, and a linear log–log relationship between the capacitance and the reciprocal of AC frequency indicating a space-charge-dominated response. By comparing the extracted dielectric constants, we further confirmed that the capacitance magnitude is primarily governed by the Sb2O3 dielectric layer. In contrast, the Au/Al/Sb2O3/MoS2/SiO2/P++Si capacitor showed stronger bias dependence and frequency dispersion, which are attributed to the combined effects of MIS carrier accumulation and Maxwell–Wagner interfacial polarization in the multilayer stack. These findings provide useful insight into the design of tunable switches and adjustable circuit elements and may also contribute to improved breakdown reliability and longer device lifetime. Moreover, the device exhibits its potential applications in tunable switches and adjustable circuit elements. This insight may further assist in improving breakdown reliability and extending device lifetime.

Structural complexity and groundwater circulation in mountain karst systems: an integrated approach combining hydrodynamic data and environmental tracers

Estimation of electron mobility in the hollow cathode plume of a Hall effect thruster with different electrical configurations

In the paper, we assess the effects of electrical configuration on the plasma properties in the near-field hollow cathode discharge that is center mounted on a Hall effect thruster. The axial profile of the electron density and temperature is obtained using incoherent laser Thomson scattering for three electrical configurations of the thruster body, i.e., grounded, floating, and cathode-tied. The effective electron mobility is estimated using a one-dimensional plasma fluid model with the measurement data as an input to the model. The estimation using the data-driven framework reveals that the electron conductivity is the highest when the thruster body is electrically grounded while the electron conductivity is comparable between the floating and cathode-tied configurations, indicating that the current path and electron dynamics of the hollow cathode discharge are affected by the electrical configurations.

Author Correction: Multidimensional profiling of heterogeneity in supratentorial ependymomas

Damage evolution mechanism and energy response of sandstone under triaxial compression

Unraveling cavity-like modes of two-dimensional broad band hyperbolic metamaterial and their coupling to quantum emitters

Hyperbolic metamaterials (HMMs) are artificially engineered materials that exhibit hyperbolic dispersion of light propagating through them. These have been extensively studied for tailoring the propagation of light. Most studies use an effective medium approach, which is extremely useful, although it misses out on properties that can arise from the microscopic details of the HMM. In particular, the HMM can have cavity-like modes, and it is important to understand such modes and their relevance in light propagation and the coupling of the HMM to quantum emitters. In this work, we explore the cavity-like modes of the silver nanowire-alumina two-dimensional HMM, which remain on top of the broad response of the HMM. These modes define the characteristic reflection spectra. Our simulations, based on bulk metal properties, predict the observed multiple, closely spaced resonances, thereby confirming the corresponding experimental observations. These well-defined modes observed in experiments occur even though the metallic part of the HMM has Ohmic losses. Then, we present experimental results on the coupling of quantum emitters to the cavity-like modes of the HMM. We show results for both steady-state and time-resolved photoluminescence. Using these results, we extract the corresponding Purcell factors for radiative rate enhancement. Theoretical analyses of the experimental data allow the determination of the cavity coupling parameters and mode volumes. This work elucidates the pathway to precise engineering for future applications of HMM modes in strong light–matter interactions.

Evaluation of collapsibility characteristics in deep loess strata using in-situ sand well immersion test

Abstract The significant collapse settlement of deep loess upon water infiltration poses a serious threat to engineering construction safety. Accurate evaluation of collapsibility characteristics is a critical issue in geotechnical engineering. Evaluation methods relying on laboratory tests often diverge from field results. This study focuses on the Shenheyuan loess. It conducts in-situ sand well immersion tests to monitor water migration in the loess stratum and settlement of soil layers at various burial depths during immersion. The results are compared with laboratory collapse test data. The findings indicate that during the in-situ sand well immersion test, the monitored settlements at all points were small, well below the 70 mm criterion for self-weight collapsibility in loess. Therefore, the site is classified as a non-self-weight-collapsible site. In contrast, laboratory tests classify the site as self-weight collapsible with a collapsibility level of grade II. A comparative analysis with the adjacent site confirms that evaluating collapsibility characteristics using an in-situ sand well immersion test is more reliable. The discrepancy between the laboratory test and the in-situ sand well immersion test primarily stems from the regional correction coefficient specified in the code, which fails to account for site-specific factors, such as high groundwater levels, climatic conditions, and soils with high clay content. Finally, a preliminary site-specific correction coefficient of 0.03 is back-calculated based on the measured field response. This study demonstrates the effectiveness of the in-situ sand well immersion test for evaluating the collapsibility of deep loess. It provides an important reference for geotechnical design under similar special geological conditions.

High-quality epitaxial growth of ferroelectric Al0.9Sc0.1N on GaN by pulsed laser deposition

In this study, high-quality wurtzite Al0.9Sc0.1N thin films were grown on GaN templates via pulsed laser deposition (PLD). The influence of in situ thermal pretreatment of the substrate, growth temperature, and laser repetition rate on the microstructural evolution and electrical properties of the films was investigated. As revealed by in situ x-ray photoelectron spectroscopy, surface oxides are effectively removed through in situ thermal cleaning at 850 °C, and this step facilitates the nucleation of the (0002) orientation. Regarding growth kinetics, optimization results show that an ideal kinetic window for adatom migration is provided by a substrate temperature of 550 °C combined with a low laser repetition rate of 2 Hz. Under these optimized conditions, exceptional crystalline quality was achieved. A record-low full width at half maximum (FWHM) of approximately 180 arc sec was recorded for the (0002) plane in the x-ray rocking curve, while an FWHM as low as 175 arc sec was observed for the (101¯2) plane. This performance is comparable to state-of-the-art thin films fabricated via molecular beam epitaxy and sputtering. As revealed by temperature-dependent electrical characterization, the leakage current mechanism is dominated by Schottky emission at low electric fields, transitioning to Poole–Frenkel emission at high electric fields. Dielectric performance was significantly enhanced by the superior crystalline quality of the sample grown at 2 Hz, yielding a breakdown field of approximately 12.7 MV/cm (breakdown voltage approximately 57 V). Furthermore, distinct ferroelectric switching characteristics were exhibited by the optimized films. Collectively, these results demonstrate PLD as a competitive, cost-effective technique.

Art management platform based on virtual scenes

Enhancement of thermoelectric properties through alloying in two-dimensional halide materials

Two-dimensional (2D) copper halides represent an emerging class of semiconductors with tunable electronic and optical properties, yet their structural stability and alloying behavior remain largely unexplored. Alloying is an effective strategy for enhancing the thermoelectric response of two-dimensional materials. Using first-principles density functional theory, we investigate the structural, electronic, and thermoelectric properties of monolayer CuI–CuBr alloys. The calculations predict thermodynamically stable CuIxBr1−x solid solutions across the full compositional range, as evidenced by uniformly negative mixing enthalpies for all considered crystal symmetries. Halide substitution induces systematic lattice contraction and symmetry-dependent distortions of the Cu-centered coordination environment, leading to a monotonic reduction of the electronic bandgap with increasing Br content. Within the constant relaxation time approximation, alloying significantly enhances the electronic contribution to the thermoelectric figure of merit, leading to high calculated ZT values within the constant relaxation time approximation framework, which should be interpreted as electronic upper-limit estimates at elevated temperatures for all investigated polymorphs. These results demonstrate that alloying provides a robust and controllable route to improve thermoelectric performance in two-dimensional materials.

Simvastatin reprograms lipid metabolism in B16.F10 melanoma cells to favor an early resistant phenotype

Injection of orbital angular momentum into transition metals from first principles

We use quantum mechanical scattering calculations implemented in a basis of tight-binding muffin-tin orbitals to calculate nonequilibrium spin and orbital currents in transition metals with a view to understanding the length scale on which they decay. In the case of spin currents, the relaxation length, called the spin-flip diffusion length, is reasonably well understood. We apply our experience with spin currents to study orbitally polarized currents and find that they behave qualitatively differently. Upon injection from a lead, orbital currents decay within a few atomic layers contradicting the current interpretation of experimental results, which appear to show exponential decay on the length scale of the spin-flip diffusion length and longer. When spin–orbit coupling is included, the injected orbital current is partially converted into a spin current within a few atomic layers. This insight provides a new perspective on the physics of the orbital Hall effect.

Foreshock-induced slip transients set mainshock nucleation timing

Abstract Foreshocks are sometimes observed before earthquakes 1–13 , yet their role in controlling rupture nucleation remains unclear 1,11,14 . Classical models often assume that nucleation arises from slow, quasi-static slip governed primarily by fault weakening 15–21 , typically neglecting impulsive precursory events. Here we show, using laboratory experiments and a rate-and-state-based Griffith-like rupture framework 22 , that foreshocks, when they occur at the onset of or during nucleation, can fundamentally regulate earthquake initiation. We find that the slip burst induced by foreshocks imparts a transient sliding velocity, V min , whose magnitude is set by foreshock size and which robustly predicts both nucleation duration and spatial length. Larger foreshocks generate higher V min and trigger a more rapid transition to dynamic rupture, whereas smaller foreshocks produce long-duration quasi-static growth and very small impulses lead to ruptures entirely arresting. Extending our theoretical framework to tectonic faults, we show that foreshock and associated slow-slip sequences preceding natural earthquakes seem to follow the same scaling. These observations allow us to constrain realistic characteristic nucleation slip distances of 0.3–3.0 mm, orders of magnitude smaller than those inferred for dynamic rupture 23 . Our results demonstrate that foreshock-induced transients set the timing and potential detectability of earthquake nucleation 24 .

Biocatalytic membrane for membrane inlet mass spectrometry

The influence of atmospheric pressure plasma jet on oxidative termination of diamond surface

This study investigates the effects of atmospheric pressure plasma jet on diamond surface functionalization, which is key for plasma-assisted polishing. By varying plasma parameters including voltage waveforms, substrate temperature, reactive gas composition, and flow rate, we identify conditions that enhance hydroxyl and atomic oxygen radical formation and promote sp3-to-sp2 carbon conversion. Pulsed and sinusoidal waveforms are compared, along with the influence of pulse rise and fall times. Optical emission spectroscopy and x-ray photoelectron spectroscopy analyses show that pulsed voltages with short rise and fall times and higher substrate temperature significantly enhance surface oxidation. Increasing gas flow facilitates the generation of excited species, producing more oxygen and hydroxyl terminations. Oxygen addition quenches plasma, and the maximum hydroxyl radical yield is observed at 1500 ppm humidity.

Rill erosion dynamics in smallholder farming systems of wet tropical Africa

Abstract Tropical Africa is globally one of the most sensitive regions to accelerated soil erosion, and much of its cropland is characterised by a substantial yield gap. In particular, the White Nile-Congo ridge (NiCo) region of the eastern Democratic Republic of the Congo (DR Congo) and Uganda is a hotspot for issues relating to food security driven by soil degradation due to steep terrain, highly erosive rainfall and low soil cover. Most soil erosion studies in the region are based on plot or large-scale modelling. Both approaches lack information on inter-field connectivity processes, which are especially important in smallholder farming systems with average field sizes below 0.1 ha. To address this knowledge gap, an unmanned aerial vehicle (UAV) based high-spatial and temporal-resolution monitoring campaign was carried out over four smallholder farming areas within the eastern DR Congo and western Uganda, with substantial differences in cropland management and productivity. The campaign covered 833 individual fields, which were monitored up to twice per month (for two years) using UAV-based aerial photography to provide insight into event-based rill erosion processes and landscape connectivity. The aerial photography data were classified according to field conditions: (i) dense vegetation cover, (ii) low vegetation cover or bare soil without signs of rill erosion, (iii) low vegetation cover or bare soil with signs of rill erosion. Land-use patchiness associated with smallholder farming systems was found to reduce inter-field connectivity and to promote highly localised rill development. Furthermore, rill erosion in the NiCo region is not an episodic process but takes place regularly during the rainy season due to frequent storm events falling on bare soil in fields left fallow for individual cultivation periods. Soil erosion dynamics of smallholder farming regions in the study area, therefore, pose unresolved challenges regarding their implementation in large-scale predictions.

Sub-bandgap-light-assisted capacitance–voltage study of gap states near valence band maximums at AlSiO/GaN interfaces with and without an AlN interfacial layer

Gap states at AlSiO/GaN interfaces with and without an AlN interfacial layer (IL) have been investigated by the sub-bandgap-light-assisted capacitance–voltage (C–V) method. The thickness of the crystalline AlN IL was 0.8 nm, which is below the critical thickness. The metal–oxide–semiconductor structures formed on n-type GaN were used for the investigation. In sub-bandgap-light-assisted C–V measurements, the bias voltage was swept from the negative bias end to the positive bias end after the monochromatic sub-bandgap light was irradiated at the negative bias end and turned off. The AlN IL showed a reduced interface state density (Dit) especially around the midgap, which is clarified by sub-bandgap-light-assisted C–V measurements with the irradiation time fixed. On the basis of the irradiation time dependence of sub-bandgap-light-assisted C–V characteristics, we investigated the behavior of near-interface traps (NITs). The flatband shift (ΔVFB) of C–V characteristics in the backward direction was dependent on irradiation time. In the sample without the AlN IL, the irradiation time dependence of ΔVFB indicated the Fowler–Nordheim tunneling injection of holes into NITs at the 2.2 and 2.6 eV photon energies of the irradiated monochromatic light. Upon the insertion of the AlN IL, however, the irradiation time dependence of ΔVFB was negligible for the 2.2 eV light irradiation and completely different from the Fowler–Nordheim tunneling injection for the 2.6 eV light irradiation, indicating a possibility that a portion of photoinduced holes accumulated at the AlSiO/AlN interface.

Line × tester analysis for yield and its components of some domestic okra (Abelmoschus esculentus L. Moench) lines

Abstract The production of high-yielding and enhanced-quality cultivars of okra has attracted interest from the industry of vegetable seeds production. Thus, field experiments were conducted at El-Baramon Research Station, Horticulture Research Institute. Twenty F 1 hybrids were generated by crossing ten female lines and two male testers using a line × tester mating design. Five hybrids, (L8×T2, L4×T2, L8×T1, L4×T1 and L5×T1), showed higher pod yield compared to the other hybrids. Most of the F 1 hybrids revealed significant heterosis over mid or better parent for yield traits. The best positive heterotic cross was L8×T2 (24.27%) and (17.28%) over mid and better parent, respectively, for pod yield per plant in a desirable direction. Furthermore, the assessments of combining ability variances revealed the predominance of non-additive genetic variance over additive variance in the inheritance of these traits. Specific lines, e.g., L4, L5, L8 and L10 showed favorable gca effects and superior individual performances for pod yield per plant. Cross combinations such as L9×T1, L3×T2, L4×T2, L2×T2 and L5×T1 exhibited desirable sca effects for pod yield per plant along with superior individual performances. The results exhibited that the values of the non-additive genetic variance ( σ 2 D ) were greater than those of additive genetic variance ( σ 2 A ) for all the traits indicating the major role of non-additive gene effect in the inheritance of the studied traits. Furthermore, the narrow sense heritability varied from 0.49 to 47.37% for pod length and total yield, respectively. To sum up, this study identified superior inbreds, produced promising hybrids, showed desirable specific combining ability action and provided high estimates of useful heterosis, which could be utilized for okra hybrid production.

Structural and magnetic properties of quad-interface ferromagnetic multilayers for magnetic tunnel junction free layers

The performance of the free layer in a magnetic tunnel junction (MTJ) is critical for optimizing magnetic random access memory devices. In this study, we systematically investigate a quad-interface free-layer structure, MgO/B-FM/W/T-FM/MgO/B-FM/W/T-FM/MgO, focusing on the modulation of key magnetic properties, including saturation magnetization (Ms), magnetic dead layer thickness (tdl), perpendicular magnetic anisotropy (PMA), and interfacial anisotropy energy constant (Ki), by varying the thicknesses of the ferromagnetic (FM) and tungsten (W) layers, the annealing process, FM composition, and interfacial symmetry. Our results demonstrate that the insertion of the W layer is pivotal in achieving the transition from IPM (in-plane magnetization) to PMA. Moreover, the W layer thickness strongly influences interfacial atomic interdiffusion; as the W thickness increases, Ms decreases. The annealing process effectively suppresses dead layer growth, further enhancing magnetic performance. Comparative analysis of FeB and CoFeB systems reveals that FeB exhibits superior PMA, Ki, and Ms, owing to its more favorable 3d orbital half-filling and better lattice matching with MgO. An extremely large PMA value of 1.5 erg/cm2 has been achieved by the quad-interface free-layer structure. Finally, investigations varying the thickness ratio between the top (T-FM) and bottom (B-FM) layers highlight significant interfacial asymmetry, showing that interfacial loss in the T-FM layer is lower than in the B-FM layer. Overall, this study provides crucial experimental evidence and theoretical insight for structural engineering and comprehensive performance optimization of multi-interface MTJs.

Mangrove growth and biomass dynamics along the mud-dominated coast of French Guiana

Abstract Mangrove forests fringe the highly dynamic, mud-dominated Guianas coast, where wave-induced mobility of Amazon-derived mudbanks drives rapid coastal accretion and erosion. In French Guiana, this geomorphic instability reorganizes mangrove distribution, creating mosaics of successional stages in which stand development rarely approaches long-term equilibrium. However, it remains uncertain whether a single age–biomass relationship can represent contrasting coastal Avicennia-dominated stands and heterogeneous estuarine Rhizophora-dominated stands in this system. This study evaluates how effectively stand age, reconstructed from historical imagery, predicts stem diameter at breast height (DBH) and aboveground biomass (AGB) of Avicennia germinans and Rhizophora spp. along this coast, using chronosequence data spanning pioneer to mature stands. DBH was measured in the field, and AGB was estimated using locally validated allometric equations. Four empirical growth models (power, Gompertz, logistic, and monomolecular) were fitted using nonlinear least squares to describe age–structure and age–biomass relationships. Stand age strongly predicted DBH in Avicennia germinans but explained less variation in AGB and in both DBH and AGB for Rhizophora spp., and differences among growth functions were small. In this mud‑dominated setting, stand‑age models perform well for coastal mangroves but are less informative for estuarine mangroves. Under ongoing climate and environment‑driven change, this study highlights the need to complement stand age with environmental and structural covariates when modelling mangrove biomass and carbon stocks in both coastal and estuarine systems.