Crystal Mode Research Articles

Debus-Radziszewski Reaction Inspired In Situ "One-Pot" Approach to Construct Luminescent Zirconium-Organic Frameworks.

Metal-organic frameworks have received extensive development in the past three decades, which are generally constructed via the reaction between inorganic building units and commercially available or presynthesized organic linkers. However, the presynthesis of organic linkers is usually time-consuming and unsustainable due to multiple-step separation and purification. Therefore, methodology development of a new strategy is fundamentally important for the construction and further exploration of the applications of MOFs. Herein, we report an in situ "one-pot" strategy inspired by the Debus-Radziszewski reaction, in which the generation of organic linkers from three kinds of simple and commercially available precursors and sequential construction of MOFs are integrated into one solvothermal condition. Based on this method, two zirconium-tetracarboxylate frameworks (HIAM-4028-op and HIAM-4029-op) were successfully prepared, which exhibit bright blue and near-infrared emissions, respectively. Due to the coordinatively unsaturated metal sites and the low symmetry of HIAM-4028-op, the coordination modes in the single crystal can transfer from the pristine 8-connected Zr6 cluster to 8- and 9-connected and to 9- and 12-connected Zr6 cluster coexisting structures via secondary linker installation. To the best of our knowledge, the present work is the first time to construct MOFs using a Debus-Radziszewski reaction-inspired in situ "one-pot" strategy, which opens a new way to design and construct MOFs with specific properties and structures.

Solid-state emissions of 4H-chromenones with simple structures: mechanochromism and polymer-based doped ultralong room-temperature phosphorescence

A series of 4H-chromenones using triphenylamine and 9-phenyl-9H-carbazole as electron-donating units exhibited mechanochromic properties based on different crystal stacking modes and ultralong room-temperature phosphorescence.

Classical View on Nonclassical Crystal Growth in a Biological Setting.

Crystallization by amorphous particle attachment, a nonclassical crystal growth mode, is prevalent in minerals formed by living tissues. It allows the organism to intervene at every step of crystal growth, i.e., particle formation, stabilization, accretion, and crystallization, and thus to orchestrate biomineral morphogenesis and crystallographic texturing; all toward achieving a required functionality for the organism. Therefore, significant effort is aimed at achieving similar control and crystal growth tunability through bioinspired and biomimetic synthetic means. This Perspective examines the driving forces and the kinetics of crystallization by amorphous particle attachment in a biological setting, and through an analogy to classical molecule-by-molecule crystallization, it establishes distinct crystal growth mechanisms. It underlines the role of physics and chemistry of materials in the "Growth and Form" of biogenic minerals.

Fabry-Perot and Tamm modes hybridization in spatially non-homogeneous magneto-photonic crystal

We presented the results of studying the features of various resonant modes excitation in a spatially non-homogeneous magnetophotonic crystal with a plasmonic coating. It has been shown that in a such crystal several resonant Fabry-Perot modes and the Tamm plasmon mode are generated at once, which undergo a spectral shift inside the photonic bandgap when the thicknesses of the optical and magnetic layers of magnetophotonic crystal is change.

Densification mechanism and surface mechanical failure evolution of complex silver nanoparticle interconnection interface via pressure-assisted forced bonding

Nano-silver paste is considered the most promising die-attach material due to the small size effect and low-temperature sintering characteristics. Pressure-assisted manufacturing process can accelerate the sintering of silver (Ag) nanoparticles, forming high-quality chip interconnect interface. In this paper, molecular dynamics (MD) simulation was performed for the first time to reveal the densification mechanism and surface mechanical failure evolution behavior of complex Ag nanoparticle interconnect interface in pressure-assisted manufacturing processes. The roles of sintering pressure, sintering parameters, and nanoparticle diameter in the densification process of Ag nanoparticles were evaluated via atomic strain, mean square displacement, sintering density, and atomic layer fault analysis. External pressure can promote the formation of sintering necks through a forced mechanical action. Changing the sintering temperature can regulate the crystal evolution mode of the interface. To describe the mechanism of densification process, we propose a competitive model that correlates sintering pressure, sintering temperature, optimal steady-state sintering time, and initial system stability. Shortening the optimal sintering steady-state time of the system can make a positive contribution to sintering performance. From the perspective of improving mechanical performance, we should try to avoid the occurrence of nanoparticle morphology characteristics inside the sintered interconnect interface, which may cause sintering neck failure. The expansion and failure of random defects are beneficial for increasing mechanical reliability. This study can provide comprehensive and effective theoretical guidance for manufacturing process of high-performance chip interconnect interface.

Effects of Rb-Based Mixed Fluxes on Surface Crystal Growth of BaTaO₂N and Photocatalytic Activities

Photocatalytic water splitting has been actively studied from the viewpoint of environmental issues as a method to produce hydrogen, a clean energy source, without using fossil fuels. Oxynitride BaTaO2N is a visible light responsive photocatalyst and is expected to have high energy conversion efficiency for hydrogen production using sunlight. In a previous study, single phase BaTaO2N crystals were successfully grown by the flux method. However, the maximum activity value is only about 500 µmol/h, which is insufficient to produce enough hydrogen for practical use. One of the reasons for this is unoptimized crystal surface, such as crystal face, and lattice defects. Flux method is known as an effective method to control crystal properties, but single flux is difficult to control these crystal properties at the same time. For example, although RbCl flux can reduce defect density by minimizing elemental contamination of BaTaO2N, it is highly volatile and not effective in controlling the crystal surface. Therefore, we considered the use of multiple fluxes at the same time. This allows appropriate modification of factors related to the flux reaction field, such as viscosity, melting point, and solute-solvent interaction, while avoiding elemental contamination. This leads to flexible adjustment of the crystal growth mode, which we believe will bring crystal growth closer to ideal conditions.In this study, the effect of multi-flux on the growth mode and photocatalytic properties of BaTaO2N crystals was investigated. As an example, we report the crystal growth of BaTaO2N using mixed fluxes of RbCl, RbBr, and Rb2CO3. A single RbCl flux provided step-terrace surface structure of the BaTaO2N crystal, while an equimolar mixture of RbCl and RbBr resulted in a flatter and more rounded crystal. The visible-light responsive photocatalytic activity of the BaTaO2N crystals obtained with each flux was evaluated. The photocatalytic H2 evolution value of BaTaO2N grown in RbCl-RbBr mixed flux was about 30% of that grown in RbCl flux. This drastic change in activity may be explained by decrease of active crystal surface, including step-terrace one derived from mixed flux reaction field. We are now investigating the effect of step-terrace structure on photocatalytic activity, by tuning the surface structure using the mixed flux species. In the presentation, we will systematically report fine design of crystal growth, photocatalytic activity, and also the contribution mechanism of the mixed fluxes on them.AcknowledgementThis work was partly supported by the NEDO Green Innovation fund projects, the Strategic Innovation Program (SIP) of the Cabinet Office, and joint research with a company.

Cooling Trapped Ions with Phonon Rapid Adiabatic Passage

In recent demonstrations of the quantum charge-coupled device computer architecture, circuit times are dominated by cooling. Some motional modes of multi-ion crystals take orders of magnitude longer to cool than others because of low coolant ion participation. Here we demonstrate a new technique, that solves this issue by coherently exchanging the thermal populations of selected modes on timescales short compared to direct cooling. Using this method, which we call “phonon rapid adiabatic passage,” we can achieve subquanta temperatures from initial states with occupations as high as n¯∼200 quanta. Analogous to adiabatic rapid passage, we quasistatically couple these slow-cooling modes with fast-cooling modes using dc electric fields. When the crystal is then adiabatically ramped through the resultant avoided crossing, nearly complete phonon population exchange results. We demonstrate this on two-ion crystals, and show the indirect ground-state cooling of all radial modes—achieving an order of magnitude speedup compared to direct cooling. We also show the technique’s insensitivity to trap potential and control field fluctuations, and find that it still achieves subquanta temperatures starting as high as n¯∼200. Published by the American Physical Society 2024

Investigation of non-reciprocity and behavior of defect modes in photonic crystals incorporating Weyl semimetals

Abstract The ability to control the frequency of defect modes in photonic crystals has led to the emergence of novel applications. Researchers have recognized the unique properties of Weyl semimetals and explored their utilization in photonic crystals. This study investigates the non-reciprocal properties in photonic crystals incorporating Weyl semimetals and examines the behavior of defect modes within these crystals. This paper employs a photonic crystal containing Weyl semimetals with two different structures. Initially, the non-reciprocal properties in both structures are examined, followed by an analysis of the behavior of defect modes. The results indicate that only utilizing Weyl semimetal in the photonic crystal does not result in non-reciprocity. The arrangement of layers next to each other, or the geometry, plays a crucial role in non-reciprocity. Additionally, the behavior of defect modes varies depending on the structure type and propagation direction.

Sensitive direct converting thin film x-ray detector utilizing β-Ga2O3 fabricated via MOCVD

Ga2O3 has been considered as one of the most suitable materials for x-ray detection, but its x-ray detection performance is still at a low level due to the limitation of its quality and absorbance, especially for hard x-ray. In this work, the effects of growth temperature and miscut angle of the sapphire substrate on the crystal quality of Ga2O3 thin films were investigated based on the MOCVD technique. It was found that the crystal growth mode was transformed from island growth to step-flow growth using miscut sapphire substrates and increasing growth temperature, which was accompanied by the improvement of the crystal quality and the reduction of the density of trapped states. Ga2O3 films with optimal crystal quality were finally prepared on a 4° miscut substrate at 900 °C. The x-ray detector based on this film shows good hard x-ray response with a sensitivity of 3.72 × 105μC·Gyair−1·cm−2. Furthermore, the impacts of Ga2O3 film crystal quality and trap density on the x-ray detector were investigated in depth, and the mechanism of the photoconductive gain of the Ga2O3 thin-film x-ray detector was analyzed.

Quantum effect in a hybrid bose-einstein condensate opto-magnomechanical system

Abstract We present a hybrid opto-magno-mechanical cavity system consisting of an optical cavity that creates an opto-mechanical cavity with a fixed mirror, a magnon mode in a ferrimagnetic crystal linked to the movable mirror and an intracavity Bose–Einstein condensate. The mechanical displacement is coupled to the magnon by the magnetostriction force and to the optical cavity by the radiation pressure, and the latter is also weakly coupled to a Bose–Einstein condensate. We provide a strategy to measure and quantify entanglement using logarithmic negativity. In addition, we study the quantum or EPR steering in order to present the stationary quantum steering. We consider that all composite modes in our model are given in a Gaussian state described by a covariance matrix. In these studies, we focus on the interaction between the Bose–Einstein condensate and the magnonic modes in a ferrimagnetic crystal. It is important to note that we use experimentally controllable realizable parameters to observe the interaction of modes at temperatures in the microkelvin range.

Preparation of a trans-free fat blend to substitute partially hydrogenated oil

Partially hydrogenated oil (PHO) possesses a mild flavor and exceptional processing characteristics, making it historically the primary choice for creamer. The discovery of health problems of trans fatty acids has accelerated the development of alternative fats. This study aimed to develop an optimal PHO alternative fat by physical blending. Based on the correlation between physicochemical properties and sensory attributes, soybean oil, fully hydrogenated palm kernel oil, and fully hydrogenated soybean oil (45/45/10, w/w/w) were selected to make the alternative fat. The fat blend exhibited a solid fat content (SFC) curve identical to PHO, along with similar melting crystallization behavior, crystal nucleation pattern and growth mode, viscosity (705 mPa s), and taste profile. Pearson correlation analysis was used to further clarify the correlation between properties and tastes. The result showed that the SFCs and fatty acid compositions have strong correlations with tastes. It provides a reference scheme for preparing fats with ideal tastes.

Optimization of polypropylene high-strength injection molding welding and interface structure analysis

Secondary injection molding is an effective method for joining polymer parts, where the weld interface plays a critical role in the overall performance of the part. This study discusses the influence of injection molding parameters on the interface strength of polypropylene and polypropylene (PP-PP) secondary injection molding and analyzes the welding interface structure. The injection molding parameters for PP-PP were optimized using the Taguchi method and the signal-to-noise ratio (S/N). The optimal injection molding parameters were determined to be a mold temperature of 120°C, injection temperature of 350°C, and injection speed of 100 mm/s. The interface tensile strength was measured at 33.42 MPa, corresponding to 98.1% of the tensile strength of the base material. Among these parameters, mold temperature has the greatest influence on the strength of the welding interface. Secondly, polarizing microscopy, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were employed to observe and analyze the crystal structure and fracture failure modes at the interface. The results indicate that elevated injection molding parameters promote the formation of crystal nuclei and spherulite growth at the secondary melt interface, with the spherulite size at the interface significantly affecting the interface strength. This study offers valuable reference for the welding of other polymers and fiber-reinforced materials.

Microsecond electro-optic switching in the nematic phase of a ferroelectric nematic liquid crystal.

Nematic liquid crystals exhibit nanosecond electro-optic response to an applied electric field which modifies the degree of orientational order without realigning the molecular orientation. However, this nanosecond electrically modified order parameter (NEMOP) effect requires high driving fields, on the order of 108 V/m for a modest birefringence change of 0.01. In this work, we demonstrate that a nematic phase of the recently discovered ferroelectric nematic materials exhibits a robust and fast electro-optic response. Namely, a relatively weak field of 2 × 107 V/m changes the birefringence by ≈ 0.04 with field-on and-off times around 1 μs. This microsecond electrically modified order parameter (MEMOP) effect shows a greatly improved figure of merit when compared to other electro-optical switching modes in liquid crystals, including the conventional Frederiks effect, and has a potential for applications in fast electro-optical devices such as phase modulators, optical shutters, displays, and beam steerers.

Dynamic control of Lamb modes in phononic crystals

This study explores the possibilities of temporal control of one-dimensional phononic crystal consisting of a homogeneous piezoelectric plate on which metallic electrodes are structured. Previous works [1] have shown that Lamb-type guided modes in these periodically structured piezoelectric ceramic plates exhibit a tunable frequency dispersion that can be controlled by external electric circuits connected to the electrodes. In this study we develop a device enabling changes in the electric boundary conditions (EBC) from one condition to another by making use of switches driven by a microcontroller. This device agility is exploited to perform dynamic control of the crystal properties. To our knowledge, this is the first study devoted to the dynamic modulation of Lamb-type guided waves. Here, we do not simply change the EBCs as a function of time, but we create a "wave" of modulation of properties. Broadband translation of Lamb-wave dispersion curves in the frequency-wavenumber space (f, k) are observed, depending on the modulation speed. Experimentally, the translation of the S0 mode is detected. The relationship between the position of static bands and the position of bands after temporal modulation obeys a very simple vector rule in the (f, k) space. [1] Phys. Rev. B 99, 094302 (2019).

Effect of Crystal Rotation on Melt Convection and Resistivity Distribution in 200 mm Floating Zone Silicon Single Crystal Growth.

Floating silicon is particularly suitable for the production of power devices and detectors due to its high purity and high resistivity. However, when the crystal diameter increases to 200 mm, the inhomogeneous distribution of dopants in the radial direction of the crystal becomes an important factor affecting the quality of the crystal. In this paper, the melt flow and crystal interface dopant distribution of 200 mm floating zone silicon under different crystal rotation modes using 2D axisymmetric models was calculated. In the simulation, the crystal rotates unidirectionally clockwise or alternates between clockwise and counterclockwise rotations and is compared with the corresponding experimental results. The results of alternate rotation show a significant improvement in the distribution of resistivity, which is explained from the perspective of melt flow, providing ideas for the industrial production of high-quality FZ silicon crystals.

Bulk and surface modes in a one-dimensional gyro-uniaxial photonic crystal

Bulk and surface modes in a one-dimensional gyro-uniaxial photonic crystal

Damage effects of KDP crystals induced by nanosecond laser

Abstract The surface morphology, compositions, microstructures, and chemical bond vibrations of potassium dihydrogen phosphate (KDP) crystals induced by nanosecond laser with different wavelengths, at different energy density are studied by scanning electron microscopy (SEM) and infrared spectroscopy (IR) techniques. SEM results showed that with the increase of laser energy density, the damage region on KDP surfaces presented three parts evidently. And the damage area increases nonlinearly with the laser energy density, accompanied by an increase in O element contents and a decrease in P and K element contents. Meanwhile, at the same energy density, the damage area induced by the 355 nm nanosecond laser is much larger than that by the 1064 nm nanosecond laser. Infrared spectrum results revealed that the laser irradiation leads to a break in hydrogen bonds and a dehydration of KDP crystals, in conjunction with a generation of P=O and P-H bonds. Moreover, with the increase of the laser energy density, the KDP crystal is damaged firstly, and then is annealed and repaired, finally is destroyed again. In addition, after irradiation at 10 J/cm2, all vibration modes of KDP crystals weaken or even disappear, and the sever damage occurs.

Bilayer Crystals of Trapped Ions for Quantum Information Processing

Trapped-ion systems are a leading platform for quantum information processing, but they are currently limited to 1D and 2D arrays, which imposes restrictions on both their scalability and their range of applications. Here, we propose a path to overcome this limitation by demonstrating that Penning traps can be used to realize remarkably clean bilayer crystals, wherein hundreds of ions self-organize into two well-defined layers. These bilayer crystals are made possible by the inclusion of an anharmonic trapping potential, which is readily implementable with current technology. We study the normal modes of this system and discover salient differences compared to the modes of single-plane crystals. The bilayer geometry and the unique properties of the normal modes open new opportunities—in particular, in quantum sensing and quantum simulation—that are not straightforward in single-plane crystals. Furthermore, we illustrate that it may be possible to extend the ideas presented here to realize multilayer crystals with more than two layers. Our work increases the dimensionality of trapped-ion systems by efficiently utilizing all three spatial dimensions, and it lays the foundation for a new generation of quantum information processing experiments with multilayer 3D crystals of trapped ions. Published by the American Physical Society 2024

Synthesis and properties of bio-based semi-aromatic heat-resistant copolymer polyamide 5T-co-6T

ABSTRACT Herein, poly(pentanediamine terephthalamide) (PA5T) homopolymer was synthesized via a salt-forming reaction+solid state polycondensation method using bio-based 1,5-pentanediamine and terephthalic acid as the primary raw materials. To address the issue of its narrower processing window, poly(hexamethylene terephthalamide)(PA6T), which also cannot be melt processed due to the processing window is negative, was introduced into its molecular chain to synthesize poly (pentanediamine/hexanediamine terephthaloyl) (PA5T-co-6T) copolymers. The structures were investigated by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance carbon spectroscopy (13C-NMR). Furthermore, the melting temperature, crystallization temperature, thermal stability, and crystal growth mode of the polymer were tested and analyzed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and wide-angle x-ray diffraction (WAXD), respectively. The results demonstrate that the crystal growth mode gradually changes from three-dimensional spherical growth to two-dimensional disk-like or three-dimensional spherical growth with the increase of 6T chain segment content. Simultaneously, the crystallization temperature, melting temperature, and crystallization rate of the polymer all showed a trend of decreasing first and then increasing, which was due to the combined effects of the increase in the content of 6T chain segments on the molecular-chain structure and crystal structure of the polymer. Bio-based PA5T-co-6T has excellent heat resistance and a wider processing window than PA5T and PA6T, which possesses great application prospects in the fields of automotive, electronic appliances, and LED optics.

Multiple temperatures and melting of a colloidal active crystal

Thermal fluctuations constantly excite all relaxation modes in an equilibrium crystal. As the temperature rises, these fluctuations promote the formation of defects and eventually melting. In active solids, the self-propulsion of “atomic” units provides an additional source of non-equilibrium fluctuations whose effect on the melting scenario is still largely unexplored. Here we show that when a colloidal crystal is activated by a bath of swimming bacteria, solvent temperature and active temperature cooperate to define dynamic and thermodynamic properties. Our system consists of repulsive paramagnetic particles confined in two dimensions and immersed in a bath of light-driven E. coli. The relative balance between fluctuations and interactions can be adjusted in two ways: by changing the strength of the magnetic field and by tuning activity with light. When the persistence time of active fluctuations is short, a single effective temperature controls both the amplitudes of relaxation modes and the melting transition. For more persistent active noise, energy equipartition is broken and multiple temperatures emerge, whereas melting occurs before the Lindemann parameter reaches its equilibrium critical value. We show that this phenomenology is fully confirmed by numerical simulations and framed within a minimal model of a single active particle in a periodic potential.