Atomic Structure Research Articles

帝国主義下のマッドサイエンス――蘭郁二郎「宇宙爆撃」試論―― Mad-Science under Imperialism: Ran Ikujirō’s “Space Bombing”

This paper discusses the critiques of the imperial world image in Ikujirō Ran’s unpublished work Space Bombing. In this work, the researcher Murao, who works at the Borneo branch of the Institute of Magnetics, studies a “microscopic world” in which microscopic humans live in an atomic structure. He falls into the delusion that there are a minimal world within the atomic structure and a larger world where Earth is considered as a single atom. This paper argues that Murao’s perception was based on the scientific knowledge of the scientist Hantarō Nagaoka. The cosmology reflects the wartime image of the world, and we argue that the larger world implies the Western world, the human world implies Japan, and the minimal world implies the colonial world. Moreover, we suggest that Murao’s mad science indicates that the imperial world's configuration is not an absolute domination vs.no-domination relationship, but merely a relative relationship, and that the clashes between civilizations are able to be interpreted as insane.

Atomic Structure and Chemical Elements (Islamic Perspective) Book as a Learning Resource

This research is a detailed examination of the development of the chemistry educational sources. The aims of the research are to describe (1) the validity of teaching material (2) the students' responses to the teaching material developed. The type of research is research and development (R&D), with model 4D by Thiagarajan. The stages development of 4D are define, design, develop and desseminate. The subjects of this study are students and lecturers of UIN Antasari. The data collection techniques and instruments used in this study are interview guides, questionnaires and observations. Based on the results of expert validation: validation of material experts with an average of 81% with the criteria "Very Valid" and validation of media experts with an average of 83.4% with the criteria "Very Valid" state that the teaching material developed is very valid and is suitable as teaching material. The percentage score of 91.6% with the "Very Good" criteria is obtained from the responses of 10 chemistry education students of UIN Antasari Banjarmasin to the teaching material developed. This book can be used in learning process that involves both students and lecturers. Keywords : Atomic Structure , Islamic Perspective, Self Learning Resource

Topological Octet-Rule Implementation for Deltahedral Boron Hydrides and Related Zintl Clusters of the Main-Group Elements: Flexible Octet-Rule Fulfillment by Mixed 2- and 3-Center Fractional Bonding Scenarios.

In the large class of main-group Zintl phases, the octet rule plays a key role for the polyanions following the pseudoatom concept and the 8-N rule, such that a unique correspondence between atomic partial structure and its electron count results. In the conceptual framework of the Wade's type of clusters the relations to the octet rule are less obvious, and its structural implications are not clear. For this purpose, a topological implementation of the octet rule (TORI) within a delocalized bonding scenario is introduced. It is based on the average topology of the deltahedral cluster skeletons and the octet rule applied to delocalized fractional 2- and 3-center bond distributions. For a given skeletal electron pair count SEP, TORI yields values (ttoc, ytoc) similar to the styx approach. Two hierarchically different types of octet-rule fulfillment are identified, the cluster-wise and the local one. The local octet-rule fulfillment always implies the cluster-wise one, while the converse is not true. Deltahedral clusters with different skeletal shapes but the same Wade's SEP count can be distinguished with respect to different octet-rule fulfillment. The TORI approach opens a perspective to compare Zintl phases containing Wade-type clusters with those containing 8-N type of partial structures on the basis of octet-rule implications. The main difference to the 8-N type of partial structures identified is the more flexible way of octet-rule fulfillment in the Wade's type clusters, which does not prevent them from realizing the same cluster topology with different SEP counts. The TORI approach works with delocalized fractional bonds and is consistent with the concept of PSEPT; it just adds an additional facet.

Atomic structure of In2O3 films on InSb nanowire and nanosheet

Surface reactions of indium antimonide (InSb) nanowires and nanosheets, including oxidation, often result in the performance deterioration of semiconductor devices. In this study, we characterized the oxide films of InSb nanowires/nanosheets at the atomic level. The oxide film on the nanowire is composed of In2O3, which grows in islands and layers along the (1¯11) and (002) planes of the matrix. The oxide film on the lateral side of the InSb nanosheet was amorphous and thinner than the oxide film on the nanowire. In2O3 grew via the external diffusion of indium ions. The oxide films on the InSb nanowires and nanosheets are closely related to the InSb surface features.

Sustainable Cathodic Performances of VS4 in Rechargeable Magnesium Batteries by Cobalt Substitution.

Vanadium tetrasulfide (VS4) is one of the most promising cathodic materials for rechargeable magnesium battery systems (RMBSs). Elemental substitution to expand layers, creation of sulfur vacancies, and reduction of particle sizes of VS4 are undoubtedly effective strategies to enhance cathodic performances. Experimental and DFT analysis revealed that valence states of vanadium and cobalt have been elevated from V2+ to V3+ and Co2+ to Co3+ in VS4 and that the Co-S bond length shortened due to cobalt substitution, which resulted in enhanced overall internal polarization in the layered atomic structure of VS4 by increasing cobalt concentrations. This phenomenon of charge accumulation contributes toward regulated magnesiation and accommodated volume expansion while cycling, resulting in the enormous structural stability of VS4 and sustainable battery performance during a long and stable cycling at a cost of 20% capacity diminution as compared to pristine VS4 in RMBS. Hence, 9% CoVS4 demonstrated a capacity of 158 mAh g-1 at a current density of 500 mA g-1 with approximately 98% capacity retention after 1000 cycles. Sustainable cathodic performance is the most desirous feature for commercialization. This work provides insight realization regarding structural limitations and opportunities of VS4 for sustainable cathodic performances in RMBS with non-nucleophilic 0.25 mol/L (R-PhOMgCI)2-A1Cl3/THF (PMC) electrolyte and has laid a theoretical plus experimental foundation for future developments.

Atomic Structure and Electronic Properties of Pristine and O-Doped Basal-Plane Inversion Domain Boundaries in AlN

Atomic Structure and Electronic Properties of Pristine and O-Doped Basal-Plane Inversion Domain Boundaries in AlN

A robust synthetic data generation framework for machine learning in high-resolution transmission electron microscopy (HRTEM)

Machine learning techniques are attractive options for developing highly-accurate analysis tools for nanomaterials characterization, including high-resolution transmission electron microscopy (HRTEM). However, successfully implementing such machine learning tools can be difficult due to the challenges in procuring sufficiently large, high-quality training datasets from experiments. In this work, we introduce Construction Zone, a Python package for rapid generation of complex nanoscale atomic structures which enables fast, systematic sampling of realistic nanomaterial structures and can be used as a random structure generator for large, diverse synthetic datasets. Using Construction Zone, we develop an end-to-end machine learning workflow for training neural network models to analyze experimental atomic resolution HRTEM images on the task of nanoparticle image segmentation purely with simulated databases. Further, we study the data curation process to understand how various aspects of the curated simulated data—including simulation fidelity, the distribution of atomic structures, and the distribution of imaging conditions—affect model performance across three benchmark experimental HRTEM image datasets. Using our workflow, we are able to achieve state-of-the-art segmentation performance on these experimental benchmarks and, further, we discuss robust strategies for consistently achieving high performance with machine learning in experimental settings using purely synthetic data. Construction Zone and its documentation are available at https://github.com/lerandc/construction_zone.

Effect of Cu incorporation in silicate and modified borate bioglass materials for health applications: insights from synchrotron-based x-ray absorption spectroscopy

This contribution investigates the effect of variable copper incorporation (x = 0.2, 1.0, 2.0, and 4.0) in silicate (45 SiO2, 24.5 CaO, 24.5 Na2O, 6P2O5wt%) and modified borate (45 B2O3, 24.5 CaO, 24.5 Na2O, 6P2O5wt%) bioglass materials to be used for bone bonding applications. X-ray absorption fine structure spectroscopy (XAFS) has been used to determine the oxidation states and local coordination structure of Cu atoms in silicate-based and borate-based glasses at the Cu K-edge (~ 8979 eV). The oxidation states of Cu atoms have been determined by near-edge XAFS (XANES) fingerprinting employing reference standard compounds of Cu. Cu (I) and Cu (II) XANES spectra of the standard reference compounds were linearly combined to fit the normalized μ(E) data of the collected XANES spectra using linear combination fitting (LCF approach). The obtained results prove that most of the silicate glass samples contain Cu2O almost exclusively, while modified borate glass samples contain a significant mixture of Cu2O and CuO phases. According to the literature, the remarkable coexistence of Cu2O and CuO phases within the borate sample, particularly when x = 4, promotes the conversion process to allow the more facile formation of hydroxy carbonate apatite (HCA). The best fit structural parameters derived from extended-XAFS (EXAFS) fitting show that the ratio between Cu (I) and Cu (II) in borate glass agreed well with that extracted from XANES analysis. XANES and EXAFS conclude that borate glass with x = 4 is the most suitable composition for bone bonding applications.

Mechanically induced stacking faults and their impact on electrical transport properties in SnSe

In van der Waals (vdW) layered thermoelectric materials, stacking faults play a pivotal role in determining their physical and transport properties. However, the absence of effective methods to control these stacking faults has hindered the optimization of transport performance. Here, in situ mechanical transmission electron microscopy techniques are applied to a state-of-the-art vdW thermoelectric compound, SnSe, to manipulate the generation of stacking faults. A comprehensive analysis of the atomic structure of stacking faults is conducted, and energy barrier calculations reveal the slip pathways of interlayer slips inducing these stacking faults. Furthermore, first-principles calculations demonstrate that introducing stacking faults can enhance thermoelectric performance by promoting band convergence and facilitating charge transport. These results provide a comprehensive understanding of stacking faults and present distinctive opportunities for structure manipulation to enhance functional properties in vdW layered materials.

Ultrathin Boron Growth onto Nanodiamond Surfaces via Electrophilic Boron Precursors.

Diamond as a templating substrate is largely unexplored, and the unique properties of diamond, including its large bandgap, thermal conductance, and lack of cytotoxicity, makes it versatile in emergent technologies in medicine and quantum sensing. Surface termination of an inert diamond substrate and its chemical reactivity are key in generating new bonds for nucleation and growth of an overlayer material. Oxidized high-pressure high temperature (HPHT) nanodiamonds (NDs) are largely terminated by alcohols that act as nucleophiles to initiate covalent bond formation when an electrophilic reactant is available. In this work, we demonstrate a templated synthesis of ultrathin boron on ND surfaces using trigonal boron compounds. Boron trichloride (BCl3), boron tribromide (BBr3), and borane (BH3) were found to react with ND substrates at room temperature in inert conditions. BBr3 and BCl3 were highly reactive with the diamond surface, and sheet-like structures were produced and verified with electron microscopy. Surface-sensitive spectroscopies were used to probe the molecular and atomic structure of the ND constructs' surface, and quantification showed the boron shell was less than 1 nm thick after 1-24 h reactions. Observation of the reaction supports a self-terminating mechanism, similar to atomic layer deposition growth, and is likely due to the quenching of alcohols on the diamond surface. X-ray absorption spectroscopy revealed that boron-termination generated midgap electronic states that were originally predicted by density functional theory (DFT) several years ago. DFT also predicted a negative electron surface, which has yet to be confirmed experimentally here. The boron-diamond nanostructures were found to aggregate in dichloromethane and were dispersed in various solvents and characterized with dynamic light scattering for future cell imaging or cancer therapy applications using boron neutron capture therapy (BNCT). The unique templating mechanism based on nucleophilic alcohols and electrophilic trigonal precursors allows for covalent bond formation and will be of interest to researchers using diamond for quantum sensing, additive manufacturing, BNCT, and potentially as an electron emitter.

Conformation-assisted solid-solid phase transition of LiTFSI electrolyte salt and the lithium ion coordination

Single crystal growth and characterization of the lithium bis(trifluoromethyl sulfonyl)imide (LiTFSI), the most common electrolyte salt for lithium-ion batteries, have been performed and succeeded in unraveling the atomic structures of its different crystalline phases. The structures of two crystalline phases (phase I: orthorhombic, Pccn; phase II: monoclinic, P21/c) have been determined through temperature-dependent X-ray crystallography of the LiTFSI single crystal on heating, and the solid-solid phase transformation between phase I and phase II has been dictated. Interestingly, a conformational change of TFSI⁻ from transoid to cisoid has been discovered during the transition from phase I to phase II, which has been further confirmed by the temperature-dependent Raman spectroscopy. The coordination of Li⁺ with the TFSI⁻ ions of different conformations has been also elucidated in the polymorphic crystalline structures. The solid-solid phase transformation of the first-order leads to the cracking of the LiTFSI crystal, probably along the lithium-ion or the fluorine-rich layer in phase II. In the molten state, the coexistence of the transoid conformation and the cisoid conformation is found in the TFSI⁻ ions, affirming the recent observation in the concentrated non-crystalline state. This work is anticipated to shed light on the (de)solvation and the transport of lithium ions in complex fluids encompassing LiTFSI electrolyte solutions from the structural aspects.

Blurred interface induced control of electrical transport properties in Josephson junctions

The interfacial microstructures of Josephson junctions are vital for understanding the microscopic mechanism to improve the performance of superconducting qubits further. However, there remain significant concerns about well understanding the correlation between atomic structures and electrical behaviors. Here, we propose a new method to define the interface of the barrier in Josephson junctions, and investigate the factors that affect the electrical properties of junctions using material analysis techniques and first principles. We find that the aluminium–oxygen ratio of the interface contributes greatly to the electrical properties of junctions, which is consistent with the conclusions obtained by utilizing the generative adversarial network for data augmentation. When the aluminium–oxygen ratio of the interface is 0.67–1.1, the model exhibits a lower barrier height and better electrical properties of the junction. Moreover, when the thickness of the barrier is fixed, the impact of the aluminium–oxygen ratio becomes prominent. A detailed analysis of Josephson junctions using a microscopic model has led to identifying of process defects that can enhance the yield rate of chips. It has a great boost for determining the relationship between microstructures and macroscopic performances.

The peeling behavior of compliant nano-films in adhesive contact with a planar rigid substrate: Insights from molecular dynamics and continuum mechanics

Peeling compliant nano-films from supporting substrates is crucial in the mechanical exfoliation and transfer processes. However, the peeling behavior, especially concerning the peeling stiffness and peak peeling force, exhibits intricate interplay with the geometric and material properties of nano-films, as well as interfacial interactions, which have yet to be fully elucidated. In this work, both classical molecular dynamics (MD) simulations and continuum analysis are adopted to investigate the entire peeling process of compliant nano-films from a planar rigid substrate. Considering the atomic structure and van der Waals (vdW) interactions at the interface, we establish a continuum mechanics model to describe the entire peeling process, encompassing the initial, transitional, steady-state, and unstable peel-off stages. The theoretical predictions are reasonably consistent with the results obtained by MD simulations. The effects of film length and interface toughness on the peeling process, the peeling stiffness and peak peeling force, are thoroughly investigated, and a phase diagram for the peeling deformation modes is quantitatively constructed. Finally, dimensional analysis yields scaling relations for the peak peeling force in terms of the length and bending stiffness of compliant nano-films, as well as the governing parameters for interfacial vdW interactions. These results contribute to a better understanding of the peeling mechanics of various two-dimensional nano-films (e.g., graphene, hexagonal boron nitride, and molybdenum disulfide) adhered to substrates.

CSA-doped PANI-CNT nano composites for Ku band microwave shielding applications

The major concern in high-frequency communication is electromagnetic interference. To address this, there are several material composites developed. This article focuses on a cost-effective development method for synthesizing CSA-doped PANI-CNT nanocomposites for microwave shielding applications. The nanocomposite is prepared using chemical polymerization. The chemical structure, surface characteristics and atomic structure of the material are characterized using FTIR, XRD, SEM, and TEM, respectively. The EMI shielding characteristics of the synthesized material are investigated as a function of weight percentage of CNT in PANI. The efficacy of the developed material is studied using the waveguide method. The analysis reveals good improvement in the shielding at the X and Ku-band frequencies.

Imaging Anisotropic Proton Intercalation in Photochromic MoO3.

Protonation represents a fundamental chemical process with promising applications in the fields of energy, environment, and memory devices. Probing the protonation mechanism, however, presents a formidable challenge owing to the elusiveness of intercalated protons. In this work, we utilize the atomic and electronic structure changes associated with protonation to directly image the proton intercalation pathways in α-MoO3 induced by UV illumination. We reveal the anisotropic intercalation behavior which is initiated by photocatalyzed water dissociation preferentially at the (001) edges and then propagates along the c axis, transforming α-MoO3 into HxMoO3 to realize photochromism. This photochromic process can be reversed via heating in air, leading to anisotropic proton deintercalation, also preferentially along the c axis. The observed anisotropic behavior can be attributed to the intrinsically low energy barriers for both proton migration along the c axis and water dissociation/formation at (001) edges.

Mechanical and structural properties of monatomic zirconium metallic glass under pressure variations and annealing processes: A molecular dynamics study

The aim of this study is to investigate how different pressure levels and annealing times affect the local atomic structure and mechanical properties of pure zirconium metallic glasses. Using molecular dynamics simulations with the embedded atom method, we explored how these changes influence the material's inherent characteristics. Analysis of the radial distribution function, coordination number, and Voronoi tessellation revealed a spectrum of structural arrangements in metallic glass formed across a pressure range of 0–70 GPa. Additionally, the glass transition temperature increased with increasing pressure, accompanied by reduced free volume. The annealing process, ranging from 0 to 5 ns on metallic glass synthesized under 0 GPa pressure, showed the coordination number's significance in achieving a glassy state. Regarding mechanical behavior, both elastic constants and moduli showed a progressive increase with rising pressure, while Young's modulus and hardness displayed enhanced values with longer annealing times.

Analysis method of point defects evolution in fused silica under multi-pulse nanosecond laser irradiation

Although no optically visible damage is produced in the fused silica under laser irradiation below its laser-induced damage threshold (LIDT), defect proliferation may occur due to the evolution of its internal atomic structure. The escalation in defect content leads to heightened absorption, and resulting in the degradation of the optical performance of the optics. In recent decades, there have been a lot of experimental studies on laser-induced damage and laser conditioning, but there is still a great lack of in-depth understanding and theoretical analysis of the evolution process of point defects in fused silica. In this study, the emphasis is on the evolution of point defects and fatigue damage in fused silica under multi-pulse nanosecond laser irradiation. To address this, a point-defect evolution model is developed, and the coupled evolution law of temperature and defect during laser irradiation is derived by integrating it with a numerical model. The results demonstrate that the model effectively predicts the defect evolution of fused silica under laser irradiation and facilitates the prediction of fatigue damage. It is revealed that the rate of defect evolution in fused silica is more influenced by temperature than stress, and a temperature threshold can be used to judge the condition of damage occurrence. Furthermore, through an analysis of the effect of laser fluence on defect relaxation rate, a defect relaxation method employing variable laser fluence was proposed. This study provides a reliable theoretical analysis method for understanding the fatigue damage induced by multi-pulse laser irradiation in fused silica and offers a new perspective for the annealing treatment of point defects in fused silica.

Impact of atomic packing and electronic structure on icosahedral short-range order and glass-forming ability of Zr–Cu metallic glasses

ABSTRACT Chemical and topological short-range ordering are important for glass formation in metallic alloys. Yet, it remains little understood from the viewpoint of the electronic bonding among the constituent elements of the alloys. In this work, we study CuxZr100−x, (46 ≤ x ≤ 70) metallic glasses, where the atomic packing efficiency and the electronic structure of the full icosahedra, the key short-range order structures, have been investigated in detail. To capture a realistic picture of the electronic bonding in the icosahedra in the as-quenched metastable state, DFT study of the electronic structure of the icosahedra extracted from classical molecular dynamics simulation is carried out. Results for the CunZr13−n , (4 ≤ n ≤ 9) clusters reveal that Cu6Zr7, Cu7Zr6 and Cu8Zr5 are the most abundant, electronically stable in Cu50Zr50 , Cu58Zr42 and Cu64Zr36, respectively. These three clusters also exhibit pseudo-gap in the density of states at the Fermi level – a feature linked with glass-forming ability according to the nearly-free electron approach. The partial density of states demonstrates the effect of small changes in the stoichiometry of the clusters on the s, p and d states of Cu and Zr in Cu–Cu and Cu–Zr bonding and hence, the stability of the clusters.

Quasi-1D Moiré superlattices in self-twisted two-allotropic antimonene heterostructures.

Two-dimensional heterostructures, characterized by a twist angle between individual sublayers, offer unique and tunable properties distinct from standalone layers. These structures typically introduce a realm of exotic quantum phenomena due to the appearance of new, long range periodicities associated with Moiré superlattices. Using molecular beam epitaxy, we demonstrate the growth of bi-allotropic 2D-Sb heterostructures on a W(110) substrate composed of twisted α (α-Sb) and β (β-Sb) phases of antimonene. Due to the relatively weak interaction between sublayers, the twist angle is intrinsically determined for each heterostructure, revealing its inherent self-twisted nature. The different atomic lattice symmetries of both allotropes lead to the formation of distinctive quasi-1D Moiré superlattices, while the random nature of the twist angle allows for a wide modulation of the Moiré potential landscape. The observed Moiré patterns on β-Sb/α-Sb heterostructures were compared with a simple model, revealing satisfactory agreement with the experiments and strongly validating the formation of self-twisted β-Sb/α-Sb heterostructures. The samples were characterized in situ using low energy electron microscopy and diffraction techniques providing a real-time tracking of the growth process and insight into the atomic structure of the synthesized nanostructures.

Atomic Structure and Chemistry of High-Entropy Oxide Grain Boundaries revealed by STEM Imaging, Strain Mapping, and Spectroscopy

Atomic Structure and Chemistry of High-Entropy Oxide Grain Boundaries revealed by STEM Imaging, Strain Mapping, and Spectroscopy