We report a systematic high-pressure neutron powder diffraction (HP-NPD) study of the bilayer Ruddlesden-Popper nickelate La 3 Ni 2 O 7 , in a Paris-Edinburgh press covering the pressure range...

Quasi-one-dimensional RbMn6Bi5, the first pressure-induced ternary Mn-based superconductor, exhibits a phase diagram analogous to those of cuprate and iron-based superconductors, with superconductivity neighboring antiferromagnetic order. Here, we use 55Mn and 87Rb nuclear magnetic resonance (NMR) to unravel its magnetic structure and fluctuations. Above the Néel temperature (TN), strong antiferromagnetic fluctuations dominate, characteristic of a paramagnetic state with pronounced spin-lattice relaxation rate enhancement. Below TN, a first-order phase transition establishes a commensurate antiferromagnetic order, where Mn atoms at the pentagon corners exhibit distinct magnetic moments with different orientations, while the central Mn atom carries no magnetic moment. The complex magnetic architecture, revealed by zero-field and high-magnetic-field NMR spectra, contrasts with earlier neutron diffraction models proposing uniform spin density waves, instead supporting localized moment ordering with charge rearrangement. The proximity of robust antiferromagnetic fluctuations to the high-pressure superconducting phase suggests a potential role for magnetic excitations in mediating unconventional Cooper pairing, akin to paradigmatic high-Tc systems. These findings provide critical insights into the interplay between geometric frustration, magnetic order, and superconductivity in manganese-based materials.

We report the growth and physical properties of single-crystalline Bi_2Ta_3S_6 crystallizing in P6_3/mcm space group, which comprises alternating Ta-S layers and Bi layers with each Bi atom connected with adjacent S atoms. Temperature-dependent electrical resistivity measurements reveal a superconducting transition at 0.84 K, with upper critical field 231 Oe under an out-of-plane magnetic field. The magnetization measurements confirm its nature as a type-II superconductor, with anisotropic Ginzburg-Landau parameter κ_ab = 7.67 and κ_c = 4.50. Hall measurements indicate the dominant carriers as hole. Hydrostatic pressure is applied, under which both the superconducting transition temperature and upper critical field increase sharply under low pressure before undergoing slight suppression under higher pressure. Density functional theory calculations reveal non-trivial topological surface states on (100) surface in Bi_2Ta_3S_6, which may offer a new avenue for exploring potential topological superconductivity in layered transition metal dichalcogenides.

In this work, we report that Bi2Ta3S6-family superconductors exhibit nontrivial band topology. They possess a natural quantum-well structure consisting of alternating stacks of TaS2 and honeycomb Bi layers, which contribute superconducting and topological properties, respectively. Symmetry-based indicators (Z(4); Z(2)Z(2)Z(2)) = (2; 000) reveal that the topological nature arises entirely from the Bi layers, which belong to a quantum spin Hall phase characterized by a p(x)-p(y) model on a honeycomb lattice. The topological zigzag (ZZ) and armchair (AC) edge states are obtained. Using VASP2KP, the in-plane g factors of these topological edge states are computed from the ab initio calculations: g(x/y)(ZZ) = 2.07/1.60 and g(x/y)(AC) = 0.50/0.06. The strong anisotropy of the edge-state g factors allows us to explore Majorana zero modes in the Bi monolayer on a superconductor, which can be obtained by exfoliation or molecular beam epitaxy. Furthermore, using the experimental superconducting gap Delta and the computed g factors, we obtain the phase diagram, which shows that the in-plane field B-y > 2.62 T can generate corner Majorana zero modes in the Bi monolayer of the superconductor Bi2Ta3S6. A similar paradigm also applies to the Bi2Ta3S6 bulk with the emergence of Majorana hinge states. These natural quantum-well superconductors therefore offer ideal platforms for exploring topological superconductivity and Majorana zero modes.

Quantitative effective atomic number ($$Z_{eff}$$) inversion in energy-resolved X-ray projection imaging is affected by beam hardening and detector-response-induced spectral distortion. In this study, we propose a joint beam-hardening and detector-response correction framework for thickness-decoupled $$Z_{eff}$$ inversion. A folded-spectrum forward model was established by incorporating the polychromatic X-ray source spectrum, material-dependent attenuation, and the detector response matrix of the energy-resolved photon-counting detector. Based on this model, a response-corrected spectral database was constructed using Monte Carlo simulation. The spectral mass-attenuation linearisation method was then used to reduce the nonlinear attenuation behavior caused by beam hardening, followed by $$Z_{eff}$$ inversion through reliability-weighted least-squares spectral matching. Experimental validation was performed using standard low to middle $$Z_{eff}$$ materials with theoretical $$Z_{eff}$$ values ranging from 6.5 to 13.0 under four mass-thickness conditions $$\rho t$$ = 3.0–9.0 g/cm2. The results showed improved thickness stability and quantitative agreement within the calibrated material and thickness range. The method was further applied to carbon-fiber-reinforced polymer specimens containing aluminium foil and optical-fiber inclusions. The resulting $$Z_{eff}$$ maps provided material-dependent contrast beyond conventional grayscale attenuation, suggesting the potential of the proposed framework for qualitative or semi-quantitative material discrimination in composite non-destructive testing.

Large negative magnetoresistance (NMR) has attracted tremendous attention for its unique performance in spin electronics. Up to now, most of the mechanisms proposed to explain NMR are only effective in limited systems. In an antiferromagnetic EuMgPb single crystal, we observed a large NMR up to -24% at 14 T, 10 K, excluding contributions from weak localization, chiral anomaly, and magnetic scattering. Supported by first-principles calculations, we propose that the deformation in the Fermi surface of the antiferromagnetic ground state, resulting from the breaking PT symmetry under magnetic field, primarily contributes to NMR. In this way, we provide a general mechanism for NMR that is suitable for various materials in nondisordered antiferromagnetic systems.

The advent of fourth-generation synchrotron light sources has precipitated a surge in high-dimensional angle-resolved photoemission spectroscopy (ARPES) data, rendering manual extraction of band dispersions a primary bottleneck in electronic structure analysis. While deep-learning techniques offer automation, their “black-box” nature and heavy reliance on extensive labeled training datasets often limit their interpretability and applicability in data-sparse regimes. Here, we present a robust and scalable physics-informed framework based on Markov Random Field (MRF) for the automated reconstruction of electronic band structures. By bridging idealized density functional theory (DFT) priors with noisy experimental observations, our approach implements a multi-stage pipeline that ensures both physical consistency and computational efficiency. Key methodological innovations include: A dual-path calibration module that enables precise momentum alignment and automated energy-shift optimization via second-derivative landscapes, ensuring robust theory-experiment coupling. A k-d-tree-based regularization strategy that effectively mitigates experimental noise and eliminates boundary artifacts common in traditional image-processing workflows. We validate this framework on the Kagome metal RbTi3Bi5 and the Au(111). Our results demonstrate that the model successfully disentangles complex electronic features — including high-velocity Dirac cones, subtle type-II Dirac points, and flat bands — from congested spectra. Unlike purely data-driven models, this MRF-based inference engine provides high physical interpretability and remains effective in limited-data regimes. This verifiable pipeline establishes a foundation for high-throughput analysis and paves the way for autonomous “self-driving” ARPES experiments at next-generation light sources.

Quantitative effective atomic number ([Formula: see text]) inversion in energy-resolved X-ray projection imaging is affected by beam hardening and detector-response-induced spectral distortion. In this study, we propose a joint beam-hardening and detector-response correction framework for thickness-decoupled [Formula: see text] inversion. A folded-spectrum forward model was established by incorporating the polychromatic X-ray source spectrum, material-dependent attenuation, and the detector response matrix of the energy-resolved photon-counting detector. Based on this model, a response-corrected spectral database was constructed using Monte Carlo simulation. The spectral mass-attenuation linearisation method was then used to reduce the nonlinear attenuation behavior caused by beam hardening, followed by [Formula: see text] inversion through reliability-weighted least-squares spectral matching. Experimental validation was performed using standard low to middle [Formula: see text] materials with theoretical [Formula: see text] values ranging from 6.5 to 13.0 under four mass-thickness conditions [Formula: see text] = 3.0-9.0 g/cm2. The results showed improved thickness stability and quantitative agreement within the calibrated material and thickness range. The method was further applied to carbon-fiber-reinforced polymer specimens containing aluminium foil and optical-fiber inclusions. The resulting [Formula: see text] maps provided material-dependent contrast beyond conventional grayscale attenuation, suggesting the potential of the proposed framework for qualitative or semi-quantitative material discrimination in composite non-destructive testing.

To enable non-destructive quantitative characterization of constituent content in C/C–SiC ceramic-matrix composites, this study develops a physics-guided framework based on multispectral photon-counting X-ray detection. In practical photon-counting measurements, multispectral attenuation features are jointly distorted by detector-response non-idealities, including charge sharing, K-escape, and finite energy resolution, as well as by beam-hardening effects from the polychromatic X-ray source. To address this coupled problem, a Geant4 11.2-based detector-response model was incorporated into a unified correction workflow together with beam-hardening compensation, so that physically consistent multispectral attenuation vectors could be recovered for subsequent constituent inversion rather than merely for spectrum restoration. On this basis, a fine-grained theoretical database covering different SiC mass fractions was established, and quantitative constituent inversion was achieved by matching the corrected attenuation features to the database. Experimental results show that the proposed framework effectively suppresses thickness-dependent bias in attenuation measurements and yields an average relative error below 3% for pure aluminum. For C/C–SiC composites, the SiC mass fraction can be quantified with an accuracy better than 3 wt%. These results demonstrate that the proposed method provides a practical non-destructive route for constituent-content characterization in heterogeneous ceramic-matrix composites and is valuable for manufacturing quality control and in-service assessment.

Development of effective cesium-based catalyst is important for methyl methacrylate (MMA) production via onestep aldol reaction. Herein, a kind of Cs/Zr-SiO2 catalyst was prepared by sol-gel method and the acid-base properties and their balance could be controllably regulated. The influence of catalyst preparation conditions including Si/Zr ratio and water content on the structure and acid-base properties of Cs/Zr-SiO2 was demonstrated, which consequentially affected catalytic performance. The formation of Si-O-Zr and Cs-O-Si structure was identified as the dominant Lewis acid and base sites and the acid site density can be enhanced by 1-fold when using sol-gel method. In addition, the MP conversion could reach 37 % with MMA selectivity of 85 % at the optimal condition. Kinetic studies revealed that the activation barrier on the modified 10Cs/Zr-SiO2 exhibited the lowest activation energy of 110.9 kJ/mol. Besides, the initial catalytic activity could still maintain after 800 h recycling, with single-pass life of 160 h.

Quasi-one-dimensional materials AMn_6Bi_5 (A = Na, K, Rb, Cs) exhibit unique electronic behaviors such as antiferromagnetism, charge density waves, and pressure-induced superconductivity. Thus, they serve as a suitable model system to investigate emergent quantum phenomena produced by the interactions among spin, charge, and lattice. Here we report the magnetotransport properties of KMn_6Bi_5, revealing a cascade of temperature-dependent carrier dynamics. Below 5 K, the system, despite its anisotropic electronic structure, could be effectively described by an isotropic two-band model and exhibits a large, non-saturating magnetoresistance (∝ B^1.8). Upon warming, a crossover to a single-band regime occurs around 20 K, driven by the suppression of a hole pocket. Electron density recovers as antiferromagnetic gap openings gradually close from 25 to 70 K which is just below the Néel temperature. Within this temperature range, field-quenched spin fluctuations suppress magnetoresistance. Furthermore, we attribute the low-temperature resistivity upturn to the scaling behavior of magnetoresistance. These findings provide crucial insights into the interplay of dimensionality, magnetism, and electron correlations in quasi-one-dimensional magnetic semimetals.

Oxygen octahedra tilt, an important knob to tune properties of perovskite oxides and their derivatives, determines the coupling patterns and emergent states. Conventional methods, such as strain and doping, are primarily employed to modulate the magnitude of the octahedra tilt. The switching of the tilt, however, is challenging due to the intrinsic interlocked coupling. Here, we achieve the interlayer switching of NiO6 octahedral tilting via interstitial oxygen insertion in Ruddlesden-Popper Lan + 1NinO3n + 1 (n = 2). Interstitial oxygen with an alternative occupation in the rock-salt (LaO) layers induces completely opposite tilt patterns of NiO6 octahedra in neighboring perovskite (LaNiO3) layers. EELS reveals a lower unoccupied UHB and a spectral-weight transfer, which may contribute to the suppression of superconductivity in La3Ni2O7 as confirmed by our high-pressure transport experiments. This mechanism of NiO6 octahedral tilt switching is further validated in Lan + 1NinO3n + 1 (n = 1 and 3), offering a promising strategy for regulating the properties of layered perovskite oxides.

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With the development of green chemistry, researchers are eager to develop separable and recyclable catalyst for methyl propionate production through ethylene hydroesterification. Herein, a novel zeolite-encapsulated Pd complex was developed for ethylene hydroesterification with CO and methanol to methyl propionate. The introduced Pd component is coordinated with 1, 2-bis (di-tert-butyl phosphinomethyl) benzene ligand to form Pd complex, which is encapsulated in USY zeolite. This scheme solves the challenge of coupling phosphinepalladium complexes with acid promoters as heterogeneous catalysts. It was found that the increasing density of Br & Oslash;nsted acid sites on USY zeolite favors the ethylene hydroesterification. Furthermore, the influences of catalyst preparation and reaction conditions on the catalytic performance were assessed. As a result, the ethylene conversion could reach 99 % with MP selectivity of 100 % under the optimal condition. In addition, the catalytic heterogeneity and stability of zeolite-encapsulated Pd complex were investigated.

Magnetism in van der Waals semiconductors offers significant potential for fundamental research on low-dimensional magnetism and the development of high-performance two-dimensional spintronic devices. Here, we report the growth, physical properties, and first-principles calculations of a new dual-octahedral transition metal chalcogenide (DTMC) MnSi2Te4. MnSi2Te4 features a layered structure with an intralayer heterostructure, where the metal octahedra and nonmetal dimeric octahedra form zigzag chains alternately. Property characterization reveals that MnSi2Te4 is a collinear G-type antiferromagnetic semiconductor, with a Néel temperature TN of 18.6 K and a significant unsaturated negative magnetoresistance (NMR) reaching -42.5% at 9 T and 100 K. First-principles calculations on the electronic band structure demonstrate that the large NMR primarily originates from the spin splitting due to parity-time symmetry breaking. This study not only discovers a new member of DTMCs with a unique crystal structure and large NMR, but also establishes a promising platform for investigating next-generation spintronic devices.

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