Crystal State Research Articles

Excess Entropy of Metallic Glasses and Its Relation to the Glass-Forming Ability of Maternal Melts

The excess entropy ΔS with respect to the maternal crystal state has been determined from calorimetric data for 30 metallic glasses. It has been shown that the excess entropy in the supercooled liquid state ΔSsql is a universal characteristic of a glass independent of its thermal treatment. Six parameters often used to estimate the glass-forming ability of supercooled melts have been calculated for the same metallic glasses. It has been shown that all six parameters increase with ΔSsql and the glass-forming ability of supercooled melts increases with their structural disorder. A possible mechanism to implement this relation has been discussed.

Single‐Luminophore Molecular Engineering for Rapidly Phototunable Solid‐State Luminescence

AbstractSmart materials enabling emission intensity or wavelength tuning by light stimulus have attracted attention in cutting‐edge fields. However, due to the general limitation of the dense molecular stacking (in solid states, especially in crystals) on photoresponsivity, constructing rapidly phototunable solid‐state luminescent systems remains challenging. Herein, we present a new luminophore that serves as both a photoresponsive and a luminous group with enhanced conformational freedom to attain this goal, namely, relying on photoexcitation‐induced molecular conformational change of an ionized persulfurated arene based on weak intermolecular aliphatic C−H⋅⋅⋅π interaction. Together with the phosphorescence characteristic of the molecule itself, rapidly enhanced phosphorescence upon irradiation can be observed in a series of phase states, like solution state, crystal, and amorphous state, especially with a high photoresponsive rate of 0.033 s−1 in crystal state that is superior to the relevant reported cases. Moreover, a rapidly phototunable afterglow effect is achieved by extending this molecule into some polymer‐based doping systems, endowing the system with unique dynamic imaging and fast photopatterning capabilities. This single‐luminophore molecular engineering and underlying mechanism have implications for building other condensed functional materials, principally for those with stimuli responses in solid states.

Multiple Structural and Phase Transformations of MOF and Selective Hydrocarbon Gas Separation in its Amorphous, Glass Phase States

AbstractThe first wide‐view image of multiple structural and phase transformations for MOFs, ranging from crystal state transformations to the extreme limit approaching liquid/glass phase, was presented. The process involves i) an initial crystalline transformation from square‐layer framework [Co2(pybz)2(CH3COO)2] ⋅ DMF (Co2) to a 3‐fold interpenetrated and ordered vacancies contained framework [Co(pybz)2(CH3OH)2] ⋅ 2CH3OH (CoM) due to in situ disassemble‐reassemble, ii) thermal induced departure of a pair of cis‐form coordinated methanol in CoM leads to amorphous framework a‐dCoM, iii) glass transition to super‐cooled liquid scl‐dCoM, iv) obtaining MOF glass g‐dCoM upon quenching the super‐cooled liquid, and v) re‐crystallization of super‐cooled liquid generates 6‐fold interpenetrated dia‐net framework [Co(pybz)2]6n (rec‐dCoM) under further heating. The access to glass from CoM, provides a new self‐perturbation strategy to create MOF glasses without melting. The wider pore size distribution in amorphous/glassy MOFs than crystalline precursor achieved the first time selective hydrocarbon gas separation by breakthrough experiments, which bring efficient separation of 1 : 99 C2H2/C2H4 by either a‐dCoM or g‐dCoM and produce polymer grade C2H4 with purity≥99.5 % after a single adsorption process. Furthermore, the mixture of 50 : 50 C3H6/C3H8 can be separated by a‐dCoM.

Multiple Structural and Phase Transformations of MOF and Selective Hydrocarbon Gas Separation in its Amorphous, Glass Phase States.

The first wide-view image of multiple structural and phase transformations for MOFs, ranging from crystal state transformations to the extreme limit approaching liquid/glass phase, was presented. The process involves i) an initial crystalline transformation from square-layer framework [Co2(pybz)2(CH3COO)2] ⋅ DMF (Co2) to a 3-fold interpenetrated and ordered vacancies contained framework [Co(pybz)2(CH3OH)2] ⋅ 2CH3OH (CoM) due to in situ disassemble-reassemble, ii) thermal induced departure of a pair of cis-form coordinated methanol in CoM leads to amorphous framework a-dCoM, iii) glass transition to super-cooled liquid scl-dCoM, iv) obtaining MOF glass g-dCoM upon quenching the super-cooled liquid, and v) re-crystallization of super-cooled liquid generates 6-fold interpenetrated dia-net framework [Co(pybz)2]6n (rec-dCoM) under further heating. The access to glass from CoM, provides a new self-perturbation strategy to create MOF glasses without melting. The wider pore size distribution in amorphous/glassy MOFs than crystalline precursor achieved the first time selective hydrocarbon gas separation by breakthrough experiments, which bring efficient separation of 1 : 99 C2H2/C2H4 by either a-dCoM or g-dCoM and produce polymer grade C2H4 with purity≥99.5 % after a single adsorption process. Furthermore, the mixture of 50 : 50 C3H6/C3H8 can be separated by a-dCoM.

Investigations on the effect of arsenic and phosphorus atomic exchange on the origin of crystal potential fluctuations in InAsP/InP epilayers

Investigations on the effect of arsenic and phosphorus atomic exchange on the origin of crystal potential fluctuations in InAsP/InP epilayers

Impact of oxygen vacancies on the structural, electronic, and optical properties of Cu<i>2</i>O and nitrogen-doped Cu<sub>2</sub>O for optoelectronic applications: a first-principles study

This study utilizes Density Functional Theory (DFT) within the Quantum ESPRESSO framework to explore the effects of oxygen vacancies and nitrogen doping on the electronic structure and optical properties of cuprous oxide (Cu2O). Pristine Cu2O, an intrinsic p-type semiconductor, typically exhibits a direct band gap. Introducing an oxygen vacancy in the absence of a dopant broadens the band structure, leading to both direct and indirect band gap characteristics. In contrast, nitrogen doping transforms the band gap into a direct one, significantly reducing it from 1.97 eV to 1.09 eV, which deviates from previous findings due to potential variations in the initial state of the Cu2O host crystal. Furthermore, spin-polarization effects indicate spin-dependent behaviour within the material. The study also examines the absorption properties of pristine, defective, and nitrogen-doped Cu2O systems using the complex dielectric function. The results show distinct absorption peaks and transitions, with nitrogen-doped Cu2O exhibiting strong absorption in the visible light range, underscoring its potential for solar cell applications.

Multiple Broadband Infrared Topological Photonic Crystal Valley States Based on Liquid Crystals.

Spectral tunable technology has to meet the requirements of strong robustness and wide spectral range. We propose a method for the transmission and manipulation of infrared topological photonic crystal valley states based on tunable refractive index method that exhibits broad-spectrum and multi-band characteristics, along with a tunable emission angle. With this structure, different rotational directions of vortex light sources can independently excite the K valley and K' valley within the frequency band ranging from 75.64 THz to 99.61 THz. At frequencies from 142.60 THz to 171.12 THz, it is possible to simultaneously excite both the K valley and K' valley. The dual refractive index tunable design allows for the adjustment of the emission angle at a fixed frequency, enabling control over the independent excitation of either a single K valley or K' valley, as well as their simultaneous excitation. This capability has significant implications for photonic computation and tunable filtering, offering enhanced operational flexibility and expanded functionality for future optical communications and integrated optical circuits.

Rare-Earth Chalcogenides: An Inspiring Playground for Exploring Frustrated Magnetism

Abstract The rare-earth chalcogenide ARECh 2 family (A = alkali metal or monovalent ions, RE = rare earth, Ch = chalcogen) has emerged as a paradigmatic platform for studying frustrated magnetism on a triangular lattice. The family members exhibit a variety of ground states, from quantum spin liquid to exotic ordered phases, providing fascinating insight into quantum magnetism. Their simple crystal structure and chemical tunability enable systematic exploration of competing interactions in quantum magnets. Recent neutron scattering and thermodynamic studies have revealed rich phase diagrams and unusual excitations, refining theoretical models of frustrated systems. This review provides a succinct introduction to ARECh 2 research. It summarizes key findings on crystal structures, single-ion physics, magnetic Hamiltonians, ground states, and low-energy excitations. By highlighting current developments and open questions, we aim to catalyze further exploration and deeper physical understanding on this frontier of quantum magnetism.

Effect of the position of Mg replacing Ni on O3-NaNi1/3Fe1/3Mn1/3O2 on the structural stability of cathode materials

Effect of the position of Mg replacing Ni on O3-NaNi1/3Fe1/3Mn1/3O2 on the structural stability of cathode materials

Thermal and sublimation properties of cardiovascular drugs sotalol and ivabradine hydrochlorides

Thermal and sublimation properties of cardiovascular drugs sotalol and ivabradine hydrochlorides

Plastic deformation of [001]-oriented single-crystal iron under shock compression: Effects of void size

The thermomechanical behavior of materials is known to be sensitive to preexisting defects in their microstructure. In this paper, non-equilibrium molecular dynamics simulations have been used to investigate the effects of the microvoid size on the plastic deformation in single-crystal iron shock-compressed along the [001] crystallographic direction. The higher the microvoid radius, the faster the kinetics of dislocations. Thus, as the microvoid radius increases, the plastic activity evolves from a regime where the deformation is dominated by twin activities to a regime where both twin and dislocation activities play an essential role and then to a regime where the deformation is dominated by dislocation slip. Furthermore, in both defect-free and defective initial crystal states, the elastic precursor wave is observed to decay with propagation distance, resulting in a constitutive functional dependence of the yielding pressure, σE, on the plastic deformation rate, ε˙p. In the regime where both deformation twinning and dislocation slip play important roles, the constitutive behavior is consistent with the original Swegle–Grady model and is in overall agreement with experimental data and thermomechanical simulations.

Dual-band large-area topological edge states and higher-order corner states in a valley Hall photonic crystal

Dual-band large-area topological edge states and higher-order corner states in a valley Hall photonic crystal

Oriented crystalline structure in melt-drawn ultrahigh-molecular-weight polyethylene induced by entanglement networks

Oriented crystalline structure in melt-drawn ultrahigh-molecular-weight polyethylene induced by entanglement networks

Topological edge states of acoustic zigzag tubes with triangle scatterers

Tubular geometries in phononic crystals have the advantages of hosting topological edge states without breaking the underlying symmetry of the lattice. The topological relationships between the acoustic zigzag tubes and the dispersion relation of the planar phononic crystal with a zigzag edge boundary are theoretically revealed through 2D k space analysis, circumferential pressure analysis, and lattice symmetry analysis. New cutting lines of the tubes are obtained, which link the winding number of the tubes with the dispersion relation of topological edge states in the planar phononic crystal. The eigenstates analysis shows that the circumferential periodic number of a tubular edge state is regular and corresponds to a specific wavenumber in the circumferential direction. On the basis of the unveiled topological relationships, tubular edge states with tunable properties are obtained by controlling the characteristic length of the boundary scatterers. Moreover, the tubular edge states are confirmed to be highly confined and robust along the designed transmission channel. This study may present a new way to design acoustic tubes with tunability and have potential applications in robust wave propagation and miniaturized phononic devices.

In-situ preparation of lanthanide luminescent MOF hydrogel for aldehyde detection☆

In-situ preparation of lanthanide luminescent MOF hydrogel for aldehyde detection☆

Study of Curie Temperature, Ferromagnetism, and thermoelectric properties BaCo2Z4 (Z = S, Se, Te) for spintronic and energy applications

Study of Curie Temperature, Ferromagnetism, and thermoelectric properties BaCo2Z4 (Z = S, Se, Te) for spintronic and energy applications

Study on the mechanism of ROS-induced oxidative stress injury and the broad-spectrum antimicrobial performance of nickel ion-doped V6O13 powder

In this study, pure V6O13 and nickel ion-doped V6O13 powders were synthesized by a simple hydrothermal-calcination method, and their broad-spectrum antimicrobial properties and mechanisms were investigated. The crystal structure, morphology, and chemical state of the powders were thoroughly analyzed by XRD, SEM, TEM, XPS, and UV–Vis. Their antimicrobial properties and mechanisms were evaluated by the ring of inhibition, bio-SEM, live-dead cell staining, ROS detection, and protein leakage experiments. The results showed that nickel ion doping modulated the oxygen defects of V6O13, generating more reactive oxygen species and leading to more severe oxidative stress, resulting in a broad-spectrum and highly efficient antimicrobial effect. This study also revealed the antimicrobial mechanism based on oxygen defect -induced ROS production, which caused cellular oxidative stress damage, leading to leakage of intracellular substances and cell death. This study not only demonstrates the potential of V6O13 as an efficient antimicrobial agent but also provides a strong experimental basis and theoretical support for the engineering design and optimization of novel antimicrobial materials by modulating material defects through ion doping.

Continuous Space-Time Crystal State Driven by Nonreciprocal Optical Forces.

We show that the continuous time crystal state can arise in an ensemble of linear oscillators from nonconservative coupling via optical radiation pressure forces. This new mechanism comprehensively explains observations of the time crystal state in an array of nanowires illuminated with light [T. Liu et al., Nat. Phys. 19, 986 (2023).NPAHAX1745-247310.1038/s41567-023-02023-5]. Being fundamentally different from regimes of nonlinear synchronization, it has relevance to a wide range of interacting many-body systems, including in the realms of chemistry, biology, weather, and nanoscale matter.

Superconducting transition of GdBa2Cu3O7-x/La0.7A0.3MnO3 (A=Sr and Ca) bilayers governed by tunable interlayer structural coupling

Superconducting transition of GdBa2Cu3O7-x/La0.7A0.3MnO3 (A=Sr and Ca) bilayers governed by tunable interlayer structural coupling

Growth, optical and thermal properties of YbxSm1-xCa4O(BO3)3 crystals

Growth, optical and thermal properties of YbxSm1-xCa4O(BO3)3 crystals