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The development of Ge-rich GeSbTe (GGST) alloys significantly enhanced the high-temperature stability required for Phase-Change Memory technology. Previous studies on Ge enrichment in GeSbTe (GST) materials with Sb-over-Te ratio lower than one (Sb / Te < 1) highlighted the segregation into cubic Ge and cubic GST phases. Such a segregated cubic GST phase is metastable and presents a polycrystalline structure with disordered grain boundaries that could lead to structural relaxation and then to drift phenomena. In this work, using resistivity measurements, Raman spectroscopy, and in situ x-ray diffraction analyses, we demonstrate for the first time to our knowledge that GGST with Sb/Te higher than one (Sb / Te > --> 1) upon annealing leads to the direct formation of a GST hexagonal phase featuring a high growth speed, bypassing the cubic metastable phase. Combined with Ge enrichment, the increased value of the activation energy of the nucleation of Sb / Te > --> 1 GGST alloys ensures a high stability of the amorphous phase. Finally, nitrogen introduction further stabilizes the system against the crystallization, without compromising the high crystalline growth speed and the formation of the stable GST hexagonal phase in alloys with Sb / Te > --> 1. These results demonstrate the possibility to tune the crystalline structure of the segregated phases in Ge-rich GeSbTe alloys, combining the stability at high temperature of the amorphous phase with the high crystallization speed and uniformity (with larger grains) of a targeted GST phase. [ABSTRACT FROM AUTHOR]

Structures of liquid water are controversial not only in supercooled polyamorphism but also in stable bulk liquids in the high temperature and pressure range. Several experimental studies in bulk liquid have assumed the existence of three different liquid water structures. If indeed the three liquid water structures are different, they should be clearly distinguished by some measure other than density that characterizes the difference in structural order. In this study, whether the three different bulk liquid water structures are real or not is numerically verified based on molecular simulations using a reliable water molecular model. Since these liquid water structures have been suggested to be related to three different crystal structures (i.e., ice Ih, III, and V), liquid structures are sampled from the vicinity of the ice Ih-liquid coexistence point, the ice III-V-liquid triple point, and the ice V-VI-liquid triple point, respectively. An attempt is made to introduce local order parameters (LOPs) as an indicator to distinguish these structures. A fast and exhaustive LOP search is performed by the molecular assembly structure learning package for Identifying order parameters. The selected LOP distinguishes the molecular structures of three different stable liquid waters with high accuracy, providing numerical evidence that these structural orders differ from each other. Furthermore, regions of the liquid water structures are drawn on a phase diagram using the LOP, demonstrating their consistency with experimental studies. [ABSTRACT FROM AUTHOR]

Reactive molecular dynamics is used to investigate the oxidation of anisotropic silver nanoparticles (nano-Ag) of various shapes, including sphere, cube, disk, cylinder, triangle, and pyramid. The effect of the nano-Ag initial morphology on their stability and composition during oxidation is quantified. Surface oxidation at 600 K leads to the formation of a core–shell structure for all nano-Ag shapes. The surface composition of facet orientations of pristine nano-Ag can be correlated with particle stability due to their different surface energies and oxygen reactivity. In particular, pyramid and triangular nano-Ag, having a high surface fraction of (110) facets, are more prone to morphological changes upon oxidation and loss of their crystallinity, compared to nanospheres and nanocubes, which exhibit the highest stability among all shapes, attributed to the large fraction of highly coordinated atoms. Spherical and cubic nano-Ag oxidize faster, owing to their large surface fractions of (100) and (111) facets, which are more reactive than (110) ones. Understanding the effect of surface crystal structure and shape of anisotropic nano-Ag can improve the design of superior metal oxide nanomaterials with desired characteristics. [ABSTRACT FROM AUTHOR]

Topological materials are receiving significant attention for their distinctive properties and practical applications. Topological states featuring multi-fold band degeneracy are not restricted to electronic systems but also extend to phonon systems. In this investigation, we delved into the higher-order symmetry-constrained topological attributes of Nb 3 Bi, an intermetallic compound with a A15 crystal structure. Through the first-principles computations and symmetry evaluation, we tried to describe the topological phonon modes safeguarded by nonsymmorphic symmetries. Our scrutiny revealed that Nb 3 Bi possesses notable degeneracy in the phonon dispersion relation, particularly highlighted by a sixfold degenerate point situated at the R point of the Brillouin zone. In addition, we also identified cubic contact Dirac points and quadratic contact triple points at the R and Γ points, respectively. The computed phonon surface states considering two distinct terminations on the (001) and (1 1 ¯ 0) planes reveal a distinct twofold rotational symmetry arrangement. The present results offer valuable insights into the distinctive phonon attributes and surface characteristics of Nb 3 Bi, emphasizing its importance in the field of phonon topology. [ABSTRACT FROM AUTHOR]

With density functional theory (DFT), it is possible to calculate the formation energy of charged point defects and in turn to predict a range of experimentally relevant quantities, such as defect concentrations, charge transition levels, or recombination rates. While prior efforts have led to marked improvements in the accuracy of such calculations, comparatively modest effort has been directed at quantifying their uncertainties. However, in the broader DFT research space, the development of Bayesian Error Estimation Functionals (BEEF) has enabled uncertainty quantification (UQ) for other properties. In this paper, we investigate the utility of BEEF as a tool for UQ of defect formation energies. We build a pipeline for propagating BEEF energies through a formation-energy calculation and test it on intrinsic defects in several materials systems spanning a variety of chemistries, bandgaps, and crystal structures, comparing to prior published results where available. We also assess the impact of aligning to a deep-level transition rather than to the VBM (valence band maximum). We observe negligible dependence of the estimated uncertainty upon a supercell size, though the relationship may be obfuscated by the fact that finite-size corrections cannot be computed separately for each member of the BEEF ensemble. Additionally, we find an increase in estimated uncertainty with respect to the absolute charge of a defect and the relaxation around the defect site without deep-level alignment, but this trend is absent when the alignment is applied. While further investigation is warranted, our results suggest that BEEF could be a useful method for UQ in defect calculations. [ABSTRACT FROM AUTHOR]

A definition of structural diversity, adapted from the biodiversity literature, is introduced to provide a general characterization of structures of condensed matter. Using the favored local structure lattice model as a testbed, the diversity measure is found to effectively filter extrinsic noise and provide a useful differentiation between crystal and amorphous structures. We identify an interesting class of structures intermediate between crystals and glasses that are characterized by a complex combination of short-range ordering and long-range disorder. We demonstrate how the diversity can be used as an order parameter to organize various scenarios by structure change in response to increasing diversity. [ABSTRACT FROM AUTHOR]

To elucidate the epitaxial strain effect over a wide range of lattice mismatch, we investigated the structures of ∼ 25 nm thick LaNiO 3 films grown on the pseudocubic (001) surfaces of three different substrates, namely, LaAlO 3 (LAO), SrTiO 3 (STO), and DyScO 3 (DSO). Such structural information had been inferred from the intensities of a small number of Bragg reflections that relate to the NiO 6 octahedral tilting in previous studies. Here, we measured more than 100 reciprocal lattice points to derive reliable structural information. The procedure of ordinary crystal structure analysis is hampered by the multidomain structure and limited volume of measurable reciprocal space, both caused by a huge, highly symmetric substrate. To overcome this difficulty, we employed the Bayesian inference to obtain the detailed atomic positions in film samples. Octahedral tilting about the c axis was dominant for the compressively strained film grown on LAO, whereas tilting about the a and b axes was dominant for the tensile strained films grown on STO and DSO. The film lattice parameters of the samples grown on STO and DSO were nearly identical, whereas additional twofold lattice modulation, including cation displacement, was only observed in the latter. [ABSTRACT FROM AUTHOR]

In this study, Pb(Zr0.54Ti0.46)O3 films were prepared by the sol-gel method with Sm doping concentrations of 0, 0.5, 1, 1.5, 2, and 3 mol. %. Their surface morphology, density, crystal structure, piezoelectric, dielectric, and ferroelectric properties were characterized. The results indicated that, unlike Sm-doped lead zirconate titanate (PZT) ceramics, all Sm-PZT films exhibit a significant increase in the grain size compared to undoped PZT films. Moreover, Sm doping affected their crystal orientation and significantly enhanced their piezoelectric coefficient d33 and remnant polarization (Pr). Notably, the Sm-PZT film with a doping concentration of 1.5 mol. % exhibited optimal (100) orientation, achieving a high piezoelectric coefficient d33 of 279.87 pm/V, 4.55 times that of the non-doped PZT films. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are promising candidate materials for photo-driven processes. Their crystalline and tunable structure makes them well-suited for placing photoactive molecules at controlled distances and orientations that support processes such as light harvesting and photocatalysis. In order to optimize their performance, it is important to understand how these molecules evolve shortly after photoexcitation. Here, we use resonance Raman intensity analysis (RRIA) to quantify the excited state nuclear distortions of four modified UiO-68 MOFs. We find that stretching vibrations localized on the central ring within the terphenyl linker are most distorted upon interaction with light. We use a combined computational and experimental approach to create a picture of the early excited state structure of the MOFs upon photoactivation. Overall, we show that RRIA is an effective method to probe the excited state structure of photoactive MOFs and can guide the synthesis and optimization of photoactive designs. [ABSTRACT FROM AUTHOR]

Inert gases (e.g., He and Xe) can exhibit chemical activity at high pressure, reacting with other substances to form compounds of unexpected chemical stoichiometry. This work combines first-principles calculations and crystal structure predictions to propose four unexpected stable compounds of CH4Xe3, (CH4)2Xe, (CH4)3Xe, and (CH4)3Xe2 at pressure ranges from 2 to 100 GPa. All structures are composed of isolated Xe atoms and CH4 molecules except for (CH4)3Xe2, which comprises a polymerization product, C3H8, and hydrogen molecules. Ab initio molecular dynamics simulations indicate that pressure plays a very important role in the different temperature driving state transitions of CH4–Xe compounds. At lower pressures, the compounds follow the state transition of solid–plastic–fluid phases with increasing temperature, while at higher pressures, the stronger Xe–C interaction induces the emergence of a superionic state for CH4Xe3 and (CH4)3Xe2 as temperature increases. These results not only expand the family of CH4–Xe compounds, they also contribute to models of the structures and evolution of planetary interiors. [ABSTRACT FROM AUTHOR]

Pyrone-2,4-dicarboxylic acid (PDC) is a valuable polymer precursor that can be derived from the microbial degradation of lignin. The key enzyme in the microbial production of PDC is 4-carboxy-2-hydroxymuconate-6-semialdehyde (CHMS) dehydrogenase, which acts on the substrate CHMS. We present the crystal structure of CHMS dehydrogenase (PmdC from Comamonas testosteroni) bound to the cofactor NADP, shedding light on its three-dimensional architecture, and revealing residues responsible for binding NADP. Using a combination of structural homology, molecular docking, and quantum chemistry calculations, we have predicted the binding site of CHMS. Key histidine residues in a conserved sequence are identified as crucial for binding the hydroxyl group of CHMS and facilitating dehydrogenation with NADP. Mutating these histidine residues results in a loss of enzyme activity, leading to a proposed model for the enzyme's mechanism. These findings are expected to help guide efforts in protein and metabolic engineering to enhance PDC yields in biological routes to polymer feedstock synthesis.

The development of new materials typically involves a process of trial and error, guided by insights from past experimental and theoretical findings. The inverse design approach for soft-matter systems has the potential to optimize specific physical parameters, such as particle interactions, particle shape, or composition and packing fraction. This optimization aims to facilitate the spontaneous formation of specific target structures through self-assembly. In this study, we expand upon a recently introduced inverse design protocol for monodisperse systems to identify the required conditions and interactions for assembling crystal and quasicrystal phases within a binary mixture of two distinct species. This method utilizes an evolution algorithm to identify the optimal state point and interaction parameters, enabling the self-assembly of the desired structure. In addition, we employ a convolutional neural network (CNN) that classifies different phases based on their diffraction patterns, serving as a fitness function for the desired structure. Using our protocol, we successfully inverse design two-dimensional crystalline structures, including a hexagonal lattice and a dodecagonal quasicrystal, within a non-additive binary mixture of hard disks. Finally, we introduce a symmetry-based order parameter that leverages the encoded symmetry within the diffraction pattern. This order parameter circumvents the need for training a CNN and is used as a fitness function to inverse design an octagonal quasicrystal. [ABSTRACT FROM AUTHOR]

Crystal structure, bandgap, and the changes in the charge conduction mechanisms in ceramics are interrelated, and the underlying physics unifies all these different phenomena. The experimental and theoretical evaluation of the electronic properties of the solid solution of (1 − x)BaTiO3–(x)LaFeO3 (x = 0, 0.015, 0.031, 0.062) is attempted in this work. Bandgap was observed to be tunable with La/Fe doping from 3.2 eV (x = 0) to 2.6 eV (x = 0.06), while the lattice disorder was found to increase. A theoretical assessment confirms a considerable shift of valence band maxima and conduction band minima with an introduction of additional defect states within the bandgap. Electron localization was also confirmed theoretically with doping. Such changes in the electronic properties were experimentally confirmed from dielectric/AC - conductivity/impedance spectroscopy studies. From different transportation models, hopping is a preferred mechanism in the less distorted BaTiO3. However, a large polaron tunneling process can be justified for the doped samples at lower temperatures. Only at higher temperatures, a small polaron tunneling can be justified for the doped samples. The transportation is affected by the grain boundaries as much as the grains themselves. A complete analysis using Nyquist plots reveals the competing contributions of these regions to the transportation mechanism and is correlated to the disorder/distortions in the lattice in terms of the formation of oxygen vacancies. [ABSTRACT FROM AUTHOR]

Ferroelectric HfO2-based thin films have attracted much interest in the utilization of ferroelectricity at the nanoscale for next-generation electronic devices. However, the structural origin and stabilization mechanism of the ferroelectric phase are not understood because the film is typically nanocrystalline with active yet stochastic ferroelectric domains. Here, electron microscopy is used to map the in-plane domain network structures of epitaxially grown ferroelectric Y:HfO2 films in atomic resolution. The ferroelectricity is confirmed in free-standing Y:HfO2 films, allowing for investigating the structural origin for their ferroelectricity by 4D-STEM, high-resolution STEM, and iDPC-STEM. At the grain boundaries of -oriented Pca21 orthorhombic grains, a high-symmetry mixed-(R3m, Pnm21) phase is induced, exhibiting enhanced polarization due to in-plane compressive strain. Nanoscale Pca21 orthorhombic grains and their grain boundaries with mixed-(R3m, Pnm21) phases of higher symmetry cooperatively determine the ferroelectricity of the Y:HfO2 film. It is also found that such ferroelectric domain networks emerge when the film thickness is beyond a finite value. Furthermore, in-plane mapping of oxygen positions overlaid on ferroelectric domains discloses that polarization is suppressed at vertical domain walls, while it is active when domains are aligned horizontally with subangstrom domain walls. In addition, randomly distributed 180° charged domain walls are confined by spacer layers.

Glycosylation is a predominant strategy plants use to fine-tune the properties of small molecule metabolites to affect their bioactivity, transport, and storage. It is also important in biotechnology and medicine as many glycosides are utilized in human health. Small molecule glycosylation is largely carried out by family 1 glycosyltransferases. Here, we report a structural and biochemical investigation of UGT95A1, a family 1 GT enzyme from Pilosella officinarum that exhibits a strong, unusual regiospecificity for the 3'-O position of flavonoid acceptor substrate luteolin. We obtained an apo crystal structure to help drive the analyses of a series of binding site mutants, revealing that while most residues are tolerant to mutations, key residues M145 and D464 are important for overall glycosylation activity. Interestingly, E347 is crucial for maintaining the strong preference for 3'-O glycosylation, while R462 can be mutated to increase regioselectivity. The structural determinants of regioselectivity were further confirmed in homologous enzymes. Our study also suggests that the enzyme contains large, highly dynamic, disordered regions. We showed that while most disordered regions of the protein have little to no implication in catalysis, the disordered regions conserved among investigated homologs are important to both the overall efficiency and regiospecificity of the enzyme. This report represents a comprehensive in-depth analysis of a family 1 GT enzyme with a unique substrate regiospecificity and may provide a basis for enzyme functional prediction and engineering.

Engineered reverse hairpin constructs containing a partial C-heptad repeat (CHR) sequence followed by a short loop and full-length N-heptad repeat (NHR) were previously shown to form trimers in solution and to be nanomolar inhibitors of HIV-1 Env mediated fusion. Their target is the in situ gp41 fusion intermediate, and they have similar potency to other previously reported NHR trimers. However, their design implies that the NHR is partially covered by CHR, which would be expected to limit potency. An exposed hydrophobic pocket in the folded structure may be sufficient to confer the observed potency, or they may exist in a partially unfolded state exposing full length NHR. Here we examined their structure by crystallography, CD and fluorescence, establishing that the proteins are folded hairpins both in crystal form and in solution. We examined unfolding in the milieu of the fusion reaction by conducting experiments in the presence of a membrane mimetic solvent and by engineering a disulfide bond into the structure to prevent partial unfolding. We further examined the role of the hydrophobic pocket, using a hairpin-small molecule adduct that occluded the pocket, as confirmed by X-ray footprinting. The results demonstrated that the NHR region nominally covered by CHR in the engineered constructs and the hydrophobic pocket region that is exposed by design were both essential for nanomolar potency and that interaction with membrane is likely to play a role in promoting the required inhibitor structure. The design concepts can be applied to other Class 1 viral fusion proteins.

Deep ultraviolet (DUV) nonlinear optical (NLO) crystals have important applications in lithography, microfabrication, and high-resolution photoelectric spectrometer. In recent years, significant progress has been made in both the theoretical design and experimental research of DUV NLO crystals. This review aims to offer a comprehensive perspective on exploring a new generation of DUV NLO materials. First, we summarize various computer-aided strategies for crystal structure design and emphasize their significant role in advancing the discovery of DUV NLO materials. Then, we outline several representative DUV crystals of experimental synthesis. Finally, we discuss the future prospects for exploring new generations of DUV NLO materials. We believe that employing data-driven, computer-aided methods to explore DUV NLO materials will help address the current challenges in the field of DUV NLO materials research. The close integration of calculation and experimentation will unlock new opportunities. [ABSTRACT FROM AUTHOR]

The surface optical (SO) phonon replica in photoluminescence (PL) spectroscopy of nitride nanowires (NWs) was theoretically investigated in this study. The dispersive relationships of SO phonon mode in anisotropic wurtzite (WZ) and isotropic zinc-blende (ZB) crystal structure NWs with circular and square cross sections (CSs) were derived within the framework of the dielectric continuum model. Based on the energy and momentum conservation laws, a constraint relationship between the frequency and wave-number was constructed for SO phonon-assisted excitonic PL spectra in the NW structure. By combining the dispersive and constraint relationships, the frequency and wave-number of the SO phonon replica in the PL spectra could be determined. The WZ and ZB crystal structures of nitride semiconductor were considered. The influences of surface factors including the CS shape, dielectric medium, and environment temperature on the frequency and photon wavelength of the band-edge emission of the SO phonon replica were studied in detail. Numerical results reveal that the crystal structure, surface factors, and environment temperature greatly affect the frequency and photon wavelength of the band-edge emission of the SO phonon replica. The calculated results for the photon wavelength agree well with the experimental values of the SO phonon replica in AlN NWs. The results of the dielectric effect obtained here are also supported by previous experimental and theoretical results for nitrides and other semiconductor NWs. The present theoretical scheme and numerical results can be used to analyze and design the SO phonon replica in PL spectra of nanostructures. [ABSTRACT FROM AUTHOR]

Ice is different from ordinary crystals because it contains randomness, which means that statistical treatment based on ensemble averaging is essential. Ice structures are constrained by topological rules known as the ice rules, which give them unique anomalous properties. These properties become more apparent when the system size is large. For this reason, there is a need to produce a large number of sufficiently large crystals that are homogeneously random and satisfy the ice rules. We have developed an algorithm to quickly generate ice structures containing ions and defects. This algorithm is provided as an independent software module that can be incorporated into crystal structure generation software. By doing so, it becomes possible to simulate ice crystals on a previously impossible scale. [ABSTRACT FROM AUTHOR]

In this report, the high-temperature transport properties of (Dy1−xCax)(Zr0.2Hf0.2Sn0.2Ti0.2Ge0.2)O7 pyrochlore oxides with x = 0, 0.05, and 0.1 are studied in dry and humid air. The phase composition and crystal structure were determined by using x-ray and neutron diffraction. The addition of calcium to the structure caused an increase in the concentration of oxygen vacancies, indicating an ionic charge compensation mechanism. Electrical studies allowed us to determine the total electrical conductivity as a function of the synthesis atmosphere and pH2O. The electrical conductivity turned out to be at the level of ∼10−3 S/cm at 800 °C, and only a slight effect of the presence of protonic defects in the structure on the total electrical conductivity was observed. In general, the samples had a low electrical conductivity with a relatively high activation energy of conduction. [ABSTRACT FROM AUTHOR]

Tailoring the crystal structure, spin, and charge state of perovskite oxides through fluorine ion doping is an attractive and effective strategy, which could significantly modify the physical and chemical properties of base oxides. Here, BaFe1−xMnxO3−δ (x = 0, 0.1, 0.2, 0.3) and BaFe1−xMnxO2.9−δF0.1 (x = 0.1, 0.2, 0.3), belonging to 6H-type BaFeO3−δ, are prepared and investigated to evaluate the impact of F− doping. The distortion of crystal structure and the reduced average valence of Mn and Fe confirm the preference for F− substitution in the hexagonal layer, which are found as the key factors for the improved magnetic properties, including ferromagnetic ordering temperature, coercive force, and remanent magnetization. Moreover, the valence reduction of B-site ions and the increased resistance distinctly indicate the expense of electron hole via fluorine doping. This work describes the adjustment of crystal structure, electronic configuration, and ferromagnetic performance by simple F− doping, which provides a prospect for practical magnetic materials. [ABSTRACT FROM AUTHOR]

Tailoring the crystal structure, spin, and charge state of perovskite oxides through fluorine ion doping is an attractive and effective strategy, which could significantly modify the physical and chemical properties of base oxides. Here, BaFe1−xMnxO3−δ (x = 0, 0.1, 0.2, 0.3) and BaFe1−xMnxO2.9−δF0.1 (x = 0.1, 0.2, 0.3), belonging to 6H-type BaFeO3−δ, are prepared and investigated to evaluate the impact of F− doping. The distortion of crystal structure and the reduced average valence of Mn and Fe confirm the preference for F− substitution in the hexagonal layer, which are found as the key factors for the improved magnetic properties, including ferromagnetic ordering temperature, coercive force, and remanent magnetization. Moreover, the valence reduction of B-site ions and the increased resistance distinctly indicate the expense of electron hole via fluorine doping. This work describes the adjustment of crystal structure, electronic configuration, and ferromagnetic performance by simple F− doping, which provides a prospect for practical magnetic materials. [ABSTRACT FROM AUTHOR]

The high-pressure synthesis of double-core nanothreads derived from pseudo-stilbene crystals represents a captivating approach to isolate within the thread chromophores or functional groups without altering its mechanical properties. These entities can be effectively utilized to finely tune optical properties or as preferential sites for functionalization. Bibenzyl, being isostructural with other members of this class, represents the ideal system for building co-crystals from which we can synthesize double-core nanothreads wherein bridging chromophores, such as the azo or ethylene moieties, are embedded in the desired concentration within a fully saturated environment. To achieve this, a critical step is the preliminary characterization of the high-pressure behavior of crystalline bibenzyl. We report here an accurate investigation performed through state-of-the-art spectroscopic techniques, Raman and Fourier transform infrared spectroscopy, and x-ray diffraction up to 40 GPa. Our findings reveal a strongly anisotropic compression of the crystal, which determines, at pressures between 1 and 2 GPa, consistent modifications of the vibrational spectrum, possibly related to a torsional distortion of the molecules. A phase transition is detected between 9 and 10 GPa, leading to a high pressure phase where, above 24 GPa, the nanothread formation is observed. However, the observed reaction was limited in extent and required significantly higher pressures in comparison to other members of the pseudo-stilbene family. This comprehensive study is imperative in laying the foundation for future endeavors, aiming to synthesize double-core nanothreads from pseudo-stilbene crystals, and provides crucial insights into the high-pressure behavior and phase transitions of crystalline bibenzyl. [ABSTRACT FROM AUTHOR]

We study epitaxial growth, crystal structures, and magnetic properties of Fe–As compound thin films grown on GaAs (111)B substrates at various values of the As4:Fe flux ratio γ, using molecular beam epitaxy. The samples grown at low As4 flux (γ = 0.3, sample A) show mainly a body-centered-cubic (bcc) crystal structure, exhibiting ferromagnetic properties similar to bcc Fe. Meanwhile, the Fe–As samples grown at medium γ (2.7–4.5, sample group B) comprise regions of Ni2In-type FeAs (a hexagonal crystal with lattice constants of a = 0.399 nm and c = 0.536 nm), which are grown at the bottom and interface with the GaAs buffer layer, and a layer of non-stoichiometric FeAs with a DO3 structure (a = 0.522 nm) formed on the top. The DO3-structure FeAs phase contains partially transformed regions, which are characterized by thin stripes in a scanning transmission electron microscopy image. Furthermore, in the sample grown with high γ = 8.5 (sample C), a hexagonal Fe–As crystal with a large in-plane lattice constant (a = 0.691 nm and c = 0.542 nm) and threefold screw axes are observed. None of these crystal structures of Fe–As compounds has ever been reported. While sample C shows no ferromagnetism, the samples in group B exhibit strong ferromagnetism with high Curie temperature TC above 400 K. These new ferromagnetic Fe–As compounds are promising for spintronic device applications. [ABSTRACT FROM AUTHOR]

Inspired by the single-bonded nitrogen chains stabilized by tetravalent cerium, pentavalent tantalum, and hexavalent tungsten atoms, we explored the possibility of single-bonded nitrogen polymorphs stabilized by trivalent lanthanum ions. To achieve this, we utilized the crystal structure search method on the phase diagram of binary La–N compounds. We identified three novel thermodynamically stable phases, the C2/c LaN3, P-1 LaN4, and P-1 LaN8. Among them, the C2/c phase with infinite helical poly-N6 chains becomes thermodynamically stable above 50 GPa. Each nitrogen atom in the poly-N6 chain acquires one extra electron, and the spiral chain is purely single-bonded. The C2/c phase has an indirect band gap of ∼1.6 eV at 60 GPa. Notably, the band gap exhibits non-monotonic behavior, decreases first and then increases with increasing pressure. This abnormal behavior is attributed to the significant bonding of two La–N bonds at around 35 GPa. Phonon spectrum calculations and AIMD simulations have confirmed that the C2/c phase can be quenched to ambient conditions with slight distortion, and it exhibits excellent detonation properties. Additionally, we also discovered armchair-like nitrogen chains in LaN4 and the armchair and zigzag-like mixed nitrogen chains in LaN8. These results provide valuable insights into the electronic and bonding properties of nitrides under high pressure and may have important implications for the design and development of novel functional materials. [ABSTRACT FROM AUTHOR]

Piezoceramics with the formula Pb0.93Sr0.06Ba0.01(Mg1/3Nb2/3)0.035(Ni1/3Nb2/3)0.2 (Sb1/2Nb1/2)0.015(ZrxTi1−x)0.75O3 + 0.5 wt. % Li2CO3, where x = 0.51, 0.50, 0.49, 0.48, 0.47, and 0.46, have been made using the one-step solid-state method. The phase structure and electrical properties were systematically investigated in the quinary system. Here, the crystalline structure transformed gradually from the rhombohedral to tetragonal phase with decreasing Zr content. More importantly, the effective piezoelectric coefficient d33* of the ceramics demonstrates an excellent thermal stability below the Curie temperature. Meanwhile, piezoelectric ceramics with x = 0.49 exhibited the extraordinary electrical properties near the morphotropic phase boundary. A huge piezoelectric coefficient d33 = 853 pC/N, high Curie temperature TC = 152 °C, and the electromechanical coupling coefficients kp = 67.4%, kt = 63.5%, and k33 = 67.4% were obtained at the composition of x = 0.49, which may lead a promising future for the transducer applications. [ABSTRACT FROM AUTHOR]

In situ temperature-dependent crystal structure of lead-free ferroelectric perovskite Ba0.798Ca0.202Zr0.006Ti0.994O3 single crystal was characterized using x-ray diffraction from 170 to 380 K. Three phases were identified at different temperatures of 170, 220, and 298 K, revealing rhombohedral (R3m), orthorhombic (Pmm2), and tetragonal (P4mm) crystal structures, respectively. The change in the bond length and its distortion are reported for both AO12 and BO6 polyhedrons, allowing for the estimation of the spontaneous polarization. The Debye–Waller factor is reported as a function of temperature for A and B-sites. Density-functional theory calculations on the tetragonal phase were performed to obtain information on the distribution of the Ca ions, the local atomic displacements, and the ideal value of the spontaneous polarization of a defect-free crystal at 0 K. We find that Ca prefers to arrange in columnar 2D plates oriented along the tetragonal axis. The Ca ions avoid being next neighbors of Zr; however, the specific arrangement of Ca has only a minor impact on the spontaneous polarization. [ABSTRACT FROM AUTHOR]

The interplay between crystal nucleation and the structure of the metastable fluid has been a topic of significant debate over recent years. In particular, it has been suggested that even in simple model systems such as hard or charged colloids, crystal nucleation might be foreshadowed by significant fluctuations in local structure around the location where the nucleus first arises. We investigate this using computer simulations of spontaneous nucleation events in both hard and charged colloidal systems. To detect local structural variations, we use both standard and unsupervised machine learning methods capable of finding hidden structures in the metastable fluid phase. We track numerous nucleation events for the face-centered cubic and body-centered cubic crystals on a local level and demonstrate that all signs of crystallinity emerge simultaneously from the very start of the nucleation process. We thus conclude that we observe no precursor for the crystal nucleation of hard and charged colloids. [ABSTRACT FROM AUTHOR]

Zn:Yb:Tm:LiNbO3 crystals with a range of [Li]/[Nb] ratios (0.94, 1.05, 1.20, and 1.38) were grown by Czochraski technique. The influence of [Li]/[Nb] ratio on the concentration of doped elements in grown crystal was investigated by inductively coupled plasma atomic emission spectrometry (ICP-AES). The defect structures formed at different [Li]/[Nb] ratios were studied by X-ray diffraction and INFRARED spectroscopy. The results show that, when the [Li]/[Nb] ratio increases, the segregation coefficients of Yb 3 + and Tm 3 + ions increase, while the segregation coefficient of Zn 2 + ions decreases. When the [Li]/[Nb] ratio in the melt increases to 1.20, the Zn:Yb:Tm:LiNbO3 crystal approaches the stoichiometric ratio. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the growth and structure properties of Pb 1 − x EuxTe, (x = 0. 0 5) epitaxial films with 0.5–1 μ m thickness, grown on BaF2 and SiO2 substrates oriented in the (111) direction, by the molecular beam condensation method in a vacuum of 10 − 4 Pa with the use of an additional compensating source of Te vapor during the growth process. The optimal conditions for obtaining structurally perfect ( W 1 / 2 = 9 0 –100 ′ ′ ) epitaxial films were established: T sub = 5 7 3 –623 K; T Te = 4 1 0 K; υ c = 8 –9 Å/s. It was determined that conductivity inversion occurs at the temperature of the compensating source 410 K. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Considering their oriented crystalline structure and high luminescent efficiency, the exploration of multi‐component organic cocrystal systems with tunable supramolecular nanostructures and potential RGB light emission has emerged as a captivating but challenging subject. Here, we propose a straightforward synthetic strategy to precisely govern the assembly, structure and structure‐property relationship of organic cocrystals. By employing the single‐crystalline template‐assisted epitaxial growth (SCT‐EG) method, the two‐dimensional (2D) highly‐aligned cocrystal nanomeshes are firstly developed to afford an exceptional RGB trichromatic system, triggering cross‐modulation white light emission (WLE) with remarkable stability and regeneration capacity over six months. The transformation from random 1D microstructures to uniformly‐oriented 2D nanomeshes can be attributed to the regulatory competitive intermolecular π‐π, CT interactions, and partial H bond interactions among cocrystals. Moreover, the successful construction of 2D RGB trichromatic cocrystal nanomeshes system holds promise to generate full‐color display, which can function as multicolor inks for photonic dynamic recognition, information encryption, and decryption. [ABSTRACT FROM AUTHOR]

SrLaAlO 4 -based ceramics have attracted intense interest due to their high quality factor (Qf) at high frequency. However, the poor resonant frequency temperature stability (τ f) limits their practical applications. Therefore, obtaining near-zero τ f while guaranteeing high Qf values is challenging. (Zn 0.5 Ti 0.5)3+ is utilized in Sr 0.6 Ca 0.4 LaAlO 4 ceramics to improve the τ f value effectively. The relationship between the structural features and microwave dielectric properties of Sr 0.6 Ca 0.4 LaAl 1- x (Zn 0.5 Ti 0.5) x O 4 (x = 0–0.5) ceramics has been systematically investigated by XRD, Rietveld refinement, SEM, Raman spectroscopy, TEM and P–V-L theory. XRD and Raman spectroscopy reveal the effect of (Zn 0.5 Ti 0.5)3+ substitution on the evolution of the crystal structure. According to the chemical bond theory, (Zn 0.5 Ti 0.5)3+ substitution leads to the increase of the dielectric constant, which is related to the increase of the average bond ionicity, with the La–O bond contributing predominantly to the bond ionicity. The variation of the Qf values can be attributed to the densification of the ceramics, the lattice energy of the Al/Zn/Ti–O bond, and the FWHM. The τ f value is strongly affected by the coefficient of thermal expansion of the lattice and the Al/Zn/Ti–O bond valence. It is noteworthy that excellent microwave dielectric properties are obtained for Sr 0.6 Ca 0.4 LaAl 1- x (Zn 0.5 Ti 0.5) x O 4 ceramics at x = 0.4: ε r = 21.62, Qf = 87,700 GHz (at 7.23 GHz), and τ f = −1.81 ppm/°C. The above work provides deeper insights into establishing the relationship between the K 2 NiF 4 -type crystal structure and dielectric properties from the perspective of chemical bond. [ABSTRACT FROM AUTHOR]

To design novel materials suitable for high-temperature electromechanical applications, a bismuth-based ternary solid solution system, (1- x - y)BiScO 3 - y Pb(Sc 1/2 Nb 1/2)O 3 - x PbTiO 3 , with compositions situated around the morphotropic phase boundary, were designed and synthesized in the form of ceramic. The crystal structure, microstructure, dielectric, ferroelectric and piezoelectric properties, and the local polar domain structure of the ceramics were investigated in detail. The examined ceramics exhibit large grain sizes ranging from 20 μm to 45 μm, along with noteworthy characteristics, including a relatively large strain of 0.21 %, a high large-signal piezoelectric coefficient (d 33 * = 368 pm/V), a low dielectric loss (tanδ = 1.7 %), and a high Curie temperature (T C ∼ 423 °C). These enhanced properties signify the suitability of the designed ternary ceramics for future high-temperature electromechanical applications. This work demonstrates an effective approach for designing ferro-/piezoelectric materials characterized by substantial strain and low dielectric loss. [ABSTRACT FROM AUTHOR]

The amorphous/crystalline structure with superhydrophilic/superaerophobic feature has better HER activity than crystalline/crystalline phase in alkaline, neutral and simulated seawater environments. [Display omitted] The development of efficient, stable, and versatile hydrogen evolution electrocatalysts is of great meaning, but still faces challenging. Interface engineering and phase engineering have been immensely applied in the field of hydrogen evolution reaction (HER) because of their unique physicochemical properties. However, they are typically used separately, which limits their effectiveness. Herein, we propose an interface-engineered CoMo/CoTe electrocatalyst, consisting of an amorphous CoMo (a-CoMo) layer-encapsulated crystalline CoTe array, achieving the profound optimization of catalytic performance. The experimental results and density functional theory calculations show that the d-band center of the catalyst shifts further upward in contrast with its crystalline–crystalline counterpart, optimizing the electronic structure and the intermediate adsorption, thereby reducing the kinetic barrier of HER. The a-CoMo/CoTe with superhydrophilic/superaerophobic features shows excellent catalytic performance in alkaline, neutral, and simulated seawater environments. [ABSTRACT FROM AUTHOR]

In order to substitute well-studied but hard-to-deposit inorganic cathodoluminescent (CL) compounds with coordination compounds and organic ligands, it is primarily important to establish CL correlation with photoluminescence and increase CL intensity. In this paper, homo- and mixed-ligand 1,4-terephthalates and naphthalene-2,6-carboxylates of europium were studied, including a novel complex (Eu2(nda)3(BPhen)2(H2O)4) whose crystal structure was determined. They were found to display luminescence of various intensities under excitation by fast electrons, which is characteristic of Eu3+. CL intensity correlated with PLQY when the saturation regime was not reached and with PLQY/τ in the saturation regime. [ABSTRACT FROM AUTHOR]

Herein, (CH3)4NMnCl3 doped with Sb3+ single crystals were grown at room temperature. The crystal structure was confirmed by the single-crystal X-ray diffraction at 293 K. The doping of Sb3+ not only improves the excitation intensity in the blue-light region but also red emission only from Mn2+. The emission intensity (Ie) of (CH3)4NMnCl3:0.5%Sb3+ is about 1.5 times higher than that of (CH3)4NMnCl3. The internal and external quantum yield (IQY and EQY) values excited by 450 nm light for the former are 78.6% and 16.0%, which are much higher than those of the latter (56.3% and 10.7%), indicating that Sb3+ can effectively transfer energy to Mn2+. Moreover, the doping of Sb3+ is beneficial to the thermal stability. The Ie of (CH3)4NMnCl3:0.5%Sb3+ at 150 °C is about 1.2 times higher than that of (CH3)4NMnCl3 at 25 °C. Meanwhile, the white LED based on (CH3)4NMnCl3:0.5%Sb3+ also exhibits good optoelectronic performance. Hence, this work provides a new strategy to explore hybrid manganese(II) chlorides for white LEDs. [ABSTRACT FROM AUTHOR]

In this paper, four original ternary neodymium complexes, [Nd(hth)3(L)x] (where x = 1 or 2; hth = 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione and L = 1,10-phenanthroline (phen, 1), 5-bromo-1,10-phenanthroline (Brphen, 2), 5-chloro-1,10-phenanthroline (Clphen, 3), and triphenylphosphine oxide (tppo, 4), are reported. The complexes are synthesised by a two-step method and characterized thoroughly. The single crystal X-ray diffraction (SC-XRD) analysis is performed only for complex 4 due to the good quality of its crystals. The SC-XRD analysis indicates that complex 4 possesses an eight-coordinate structure in the solid state, having three hth and two tppo ligands. The 1H NMR analysis indicates that complexes 1–4 exhibit nine-coordinate structures in solution, having one coordinated water molecule besides hth and ancillary ligands. The Sparkle/PM7 optimized structures of the complexes are also presented, and complex 4 is compared with its crystal structure. Shape analyses reveal that complexes 1, 2, and 3 adopt biaugmented trigonal prism geometry, while complex 4 exhibits biaugmented trigonal prism J50 geometry. The photophysical investigations of the complexes were conducted in both solution and PMMA films in the near infrared (NIR) region. The results show that the hth ligand serves as an effective sensitizer and phen is the best antenna ligand. The TGA/DTA analysis indicates that the complexes are stable up to ∼200 °C, indicating their possible use in optoelectronic devices. Therefore, complex 4 is used as an emitting layer in a NIR-organic light-emitting device (OLED) with the following structure: ITO/MoO3 (2 nm)/β-NPB (30 nm)/TcTa:[complex 4] (20 nm, 10 wt%)/TPBi:[complex 4] (10 nm, 10 wt%)/TPBi (25 nm)/LiF (0.1 nm)/Al (100 nm). [ABSTRACT FROM AUTHOR]

We have analyzed topological motifs of whole crystal structures and unconnected non-metal sublattices in 967 borides, 721 carbides, 899 nitrides and 927 silicides of metals within the periodic net model. In addition, we have classified the topological types of connected non-metal motifs in 333 carbides and 86 nitrides containing N–N or C–C bonds. The topology of the whole structure was found to be essentially predetermined by the sublattice motif; however, there were exceptions, which were caused by geometrical distortions of the structure. In contrast, sublattices of the same type can exist in different structural and topological types. We have proposed an integral criterion 〈G3〉 of the sublattice distortion, which can also be considered as a measure of the sublattice uniformity. In most cases, the sublattices of non-metal atoms possess high uniformity, which reflects the tendency of the negatively charged atoms to be placed as distant as possible from each other. The sublattices, which have high symmetry, simple topology, and high uniformity in the most symmetrical embedding, were found to be the most suitable for the realization in different structures. The low uniformity of a sublattice indicates either strong interatomic interactions in the sublattice or its subordinate structural role. [ABSTRACT FROM AUTHOR]

Owing to their rich redox behavior and strong metal chelating ability, tetraoxolene ligands have been established as one of the foundational building blocks for multifunctional metal–organic materials. Here, we show how simple and often overlooked synthetic parameters can be used to control the structures of transition metal and lanthanide-based metal–tetraoxolene materials across multiple length scales. Through the synthesis of twelve new compounds, we provide a comprehensive survey detailing how the choice of solvent, initial ligand redox state, and in situ oxidant impact the local coordination geometry and chain architecture, as well as the crystal size and shape (e.g., rods vs. platelets). This work represents an important step towards the synthesis of new metal–tetraoxolene materials with predictable architectures and, therefore, targeted functionality. [ABSTRACT FROM AUTHOR]

A method to obtain sodium titanate nanoribbons starting from a mixture of brookite and anatase TiO₂ nanopowder is described. As-prepared TiO 2 nanopowder with a major brookite phase was used as a precursor in an alkaline hydrothermal approach, where the temperature was kept at 200 °C. The influence of hydrothermal treatment and consequent annealing temperature (T = 500 °C) on the crystal structure, phase composition, and morphology of samples were investigated by X-ray powder diffraction (XRPD), Raman and FTIR spectroscopy, and electron microscopy techniques (FESEM, HRTEM). All these methods point out that the hydrothermally treated sample, containing the NaTi 3 O 6 (OH)(H 2 O) 2 , Na 2 Ti 3 O 7 , and Na 2 Ti 9 O 19 , is dominated by layer-structured sodium hydroxititanate dihydrate. The annealing leads to the formation of rare sodium titanates, Na 3 Ti 6 O 13 and Na 2 Ti 9 O 19 , with tunnel structures where the hexatitanate with increased sodium content prevails. The photocatalytic activity of synthesized nanostructures was tested in the degradation process of Reactive Orange (RO16) azo-dye upon UV excitation. It appears that photocatalytic activity is lower after hydrothermal treatment, but subsequent annealing makes sodium titanate nanoribbons faster in the degradation of RO16. The research implies that these sodium titanate nanostructures are promising photocatalytic materials and should be considered in the future for removing different pollutants from water. [ABSTRACT FROM AUTHOR]

Boron nitride, as an excellent thermal conductive filler, has received widespread attention in the field of heat dissipation, and its interface thermal transport with organic matrix is a key issue for improving thermal conductivity. In this study, several typical modifiers are selected to modify boron nitride to improve its interfacial compatibility with epoxy resin. The composition of functional groups, crystal structure and factors affecting thermal conductivity of the modified boron nitride surface are systematically studied. The influence of main factors such as the structural characteristics of grafted molecules and the grafting functional groups on the construction of thermal conductivity channels was analyzed in detail. The results show that shorter chain length and fewer cross-linked branches are more conducive to phonon transport and propagation. The thermal conductivity of BN-KH570/EP composite at 26 wt% load reaches 1.52 W/m·K, which is 7.6 times that of pure epoxy resin. It also maintains good thermal stability at 600 °C, which provides a new idea for improving the interface interaction of boron nitride composites. [ABSTRACT FROM AUTHOR]

Ceramic compounds BaTi 1-x Fe x O with x = 0–0.2 prepared by solid state reaction technique were studied using X-ray diffraction, Raman spectroscopy, and magnetometry methods focusing on the correlation between the structure and magnetic properties. Chemical doping with Fe ions leads to a concentration driven structural transformation from the single phase tetragonal (T-) structure to the hexagonal (H-) structure with a mixed structural state stable in the concentration range 0.06 < x ≤ 0.2. Increase in the Fe ions content causes a stabilization of weak ferromagnetic state driven by the exchange interactions Fe3+ – O – Fe3+ ions strongly dependent on the structural positions of the Fe ions. Increase of the dopant content above x = 0.08 leads to a decrease of the remnant magnetization which is mainly caused by a stabilization of Fe4+ ions as well as by the lattice defects associated with oxygen vacancies formed to keep electroneutrality of the compounds. The results of the structural and magnetization measurements allowed to itemize the type of exchange interactions between Fe ions residing different structural positions of the hexagonal lattice as well as to reveal structural instability of the T- and H- phases under ambient conditions and applied electric field which shows a possibility to control the structure and magnetic properties of the mixed compounds via external stimuli. [ABSTRACT FROM AUTHOR]

Herein, (CH3)4NMnCl3 doped with Sb3+ single crystals were grown at room temperature. The crystal structure was confirmed by the single-crystal X-ray diffraction at 293 K. The doping of Sb3+ not only improves the excitation intensity in the blue-light region but also red emission only from Mn2+. The emission intensity (Ie) of (CH3)4NMnCl3:0.5%Sb3+ is about 1.5 times higher than that of (CH3)4NMnCl3. The internal and external quantum yield (IQY and EQY) values excited by 450 nm light for the former are 78.6% and 16.0%, which are much higher than those of the latter (56.3% and 10.7%), indicating that Sb3+ can effectively transfer energy to Mn2+. Moreover, the doping of Sb3+ is beneficial to the thermal stability. The Ie of (CH3)4NMnCl3:0.5%Sb3+ at 150 °C is about 1.2 times higher than that of (CH3)4NMnCl3 at 25 °C. Meanwhile, the white LED based on (CH3)4NMnCl3:0.5%Sb3+ also exhibits good optoelectronic performance. Hence, this work provides a new strategy to explore hybrid manganese(II) chlorides for white LEDs. [ABSTRACT FROM AUTHOR]

In order to compare the effect of the monophenyl ring terephthalic acid (TPA) and biphenyl rings 4,4′‐oxybisbenzoic acid (OBBA) with ether bond on poly(butylene adipate) (PBA)‐based copolyesters properties, two copolyester series poly(butylene adipate‐co‐butylene terephthalate)s (PBATs) and poly(butylene adipate‐co‐butylene oxybisbenzoate)s (PBAOs) were synthesized, and comparatively investigated. All the synthesized copolyesters had satisfactory number‐average molecular weights in the range of 26,500–73,000 g/mol. For PBATs copolyesters, the crystalline structure gradually transitioned from the monoclinic crystal structure of poly(butylene adipate) to poly(butylene terephthalate) (PBT) with increasing TPA because of the crystalline segments transformation from butylene adipate to butylene terephthalate, while PBAO copolyesters progressively shifted from the crystalline structure of PBA to the amorphous structure of poly(butylene oxybisbenzoate) (PBO) as increasing content of OBBA. The incorporation of either TPA or OBBA comonomers with rigid cyclic structure into PBA chain noticeably increased the glass transition temperature (Tg). With the same monomer molar ratio, PBAOs because of incorporation of the bicyclic comonomers presented higher Tg (range from −24.2 to 49.5°C) than that of PBATs (range from −56.5 to 22.4°C). It was found that copolyesters with bicyclic and ether bond OBBA comonomers exhibited a better flexibility in property than that with monocyclic TPA comonomers. [ABSTRACT FROM AUTHOR]

Cu:CsPbClxBr3‐x quantum dots (QDs) with different Cu‐to‐Pb molar ratios were synthesized via a solvent‐based thermal synthesis method, and highly stable blue‐light PCL@Cu:CsPbClxBr3‐x composite fibers (CFs) were prepared by electrohydrodynamic (EHD) technology. The photoluminescence (PL) properties of these Cu2+‐doped Cu:CsPbClxBr3‐x QDs and the stability of polymer encapsulation were investigated in this study. The results showed that with increasing Cu2+ concentration, the CsPbCl1.5Br1.5 QDs maintained their initial cubic crystal structure. The doping of Cu2+ ions effectively eliminated the surface defects of CsPbCl1.5Br1.5 QDs, facilitating excitonic recombination through radiative pathways. The PL quantum yield (PLQY) of Cu:CsPbCl1.5Br1.5 QDs increased to 85%. In addition, The fiber encapsulation method effectively improved the stability of the Cu:CsPbCl1.5Br1.5 QDs, After 3 days in water, the fluorescence intensity still remains at the initial 90%. Based on these results, it is believed that Cu:CsPbCl1.5Br1.5 QDs have promising applications in optoelectronic devices in the future. [ABSTRACT FROM AUTHOR]

Efficient conversion of ortho-hydrogen (o-H 2) to para-hydrogen (p-H 2) is crucial for liquid hydrogen development. In this work, FeMn catalysts were prepared using impregnation method and loaded onto HiSiV-3000 zeolite (FMO-H). FMO-Hs were characterized and tested for o-H 2 to p-H 2 conversion at 77 K. The results showed that 30 wt% HiSiV-3000 was the most favorable condition for the exposure of active sites of FeMn catalyst (FMO-3H). Additionally, compared to the monometallic Fe–3H catalyst, the addition of Mn increased disorder within the internal crystal structure and magnetization intensity of the catalyst, enhancing the paraffin conversion efficiency. At a gas hourly space velocity of 3600 h−1, the o-H 2 to p-H 2 conversion rate of FMO-3H reached to 98.4%, with an outlet p- H 2 content of 44.6%. [Display omitted] • Efficient FeMn-supported catalysts were prepared for ortho-para H 2 conversion. • Zeolite HiSiV-3000 facilitated the exposure of FeMn. • Mn addition enhanced the catalytic performance of Fe. [ABSTRACT FROM AUTHOR]

Antiferromagnetic intermetallic compound EuRhGe $_3$ 3 crystalizes in a non-centrosymmetric BaNiSn $_3$ 3 -type ($I4\, {\rm mm}$ I 4 mm ) structure. We studied its pressure-dependent crystal structure by using synchrotron powder x-ray diffraction at room temperature. Our results show a smooth contraction of the unit cell volume by applying pressure while preserving $I4\, {\rm mm}$ I 4 mm symmetry. No structural transition was observed up to 35 GPa. By the equation of state fitting analysis, the bulk modulus and its pressure derivative were determined to be 73 (1) GPa and 5.5 (2), respectively. Furthermore, similar to the isostructural EuCoGe $_3$ 3 , an anisotropic compression of a and c lattice parameters was observed. Our experimental results show a good agreement with the pressure-dependent structural evolution expected from theoretical calculations below 13 GPa. Reflecting a strong deviation from integer Eu valence, the experimental volume data appear to be smaller than those of DFT calculated values at higher pressures. [ABSTRACT FROM AUTHOR]

Uniformly coating micronic particles with metals is of main interest for a broad range of applications. This study demonstrates the feasibility of depositing pure copper on the surface of micronic alumina particles by the fluidized bed chemical vapor deposition process from the cheap and nontoxic copper acetylacetonate precursor. Thanks to the development of a preconditioning protocol, a complete fluidization of the particles organized as porous agglomerates was reached. The coating of the individual particles was favored by using conditions involving low deposition rates. The influence of key operating parameters on the process behavior and on the characteristics of the deposit was studied. The deposited copper was of cubic crystal structure without carbon nor oxide contamination. [ABSTRACT FROM AUTHOR]

Samples in the La 2 MoO 6 – Sm 2 MoO 6 – MoO 3 system were obtained using the solid-state synthesis method. The phase formation in the given compositional section was firstly studied, and the homogeneity region of the fluorite-like lanthanum-samarium molybdate was determined, as confirmed by XRD analysis including Rietveld refinement and SEM with energy-dispersive microanalysis. The fluorite-like phase contains less molybdenum than the isostructural neodymium molybdate Nd 5 Mo 3 O 16+δ. The homogeneity region of fluorite-like solid solutions has been determined, which corresponds to the La 5-x Sm x Mo 2.75 O 15.75 section in the composition range 2.5 ≤ x ≤ 3.5. The crystal structure is characterized by the splitting of cation positions and the presence of excess oxygen in the octahedral voids of the structure. Oxygen atoms in the octahedral positions are displaced from the center of the voids and enter into the molybdenum coordination sphere. The density of single-phase ceramic samples increases with the increase in samarium content. The conductive properties of single-phase ceramics were investigated in an air atmosphere using impedance spectroscopy. The total conductivity was ∼10−2 S cm−1 for La 2.5 Sm 2.5 Mo 2.75 O 15.75 at 800 °C. The grain bulk conductivity exhibits a break at a temperature of approximately 600 °C, which may be explained by the depletion of charge carriers in the structure. [ABSTRACT FROM AUTHOR]

All-solid-state batteries are typically manufactured under high pressure to decrease the resistance of the solid interface. However, until now, there has been a lack of research concerning changes in the structure of solid electrolytes owing to pressurization. Our study addresses this gap by exploring the structural modifications of the sulfide solid electrolyte Li3PS4 under high-pressure conditions. We observed a tendency for PS4 molecules to converge upon each other in both β-Li3PS4 and g-Li3PS4 crystals when subjected to a pressure of 100 MPa. In g-Li3PS4, X-ray scattering and pair distribution function analyses following pressure application and subsequent return to ambient conditions remained consistent with pre-compression measurements. Conversely, in β-Li3PS4 crystals, post-pressure X-ray scattering differed from pre-compression measurements, suggesting pressure-induced atomic rearrangement within the crystal lattice. This underscores the importance of accounting for pressure-induced structural changes, especially in computational simulation studies where crystal structures are often assumed to remain static pre- and post-pressurization. Our findings demonstrate that under high pressure, the crystal structure of Li3PS4 slightly changes by approximately 1~2%, rendering it a viable candidate for utilization as a solid electrolyte in all-solid-state batteries. [ABSTRACT FROM AUTHOR]