Lattice Order Research Articles

Phase behavior of rotationally asymmetric Brownian kites containing 90° internal angles* *Project supported by the National Natural Science Foundation of China (Grant Nos. 11874277 and 21621004, and 11704276) and the Natural Science Foundation of Tianjin, China (Grant No. 19JCQNJC14900).

Previous Monte Carlo simulations have shown that ordered tetratic phases can emerge in a dense two-dimensional Brownian system of rotationally asymmetric hard kites having 90° internal angles. However, there have been no experimental investigations yet to compare with these simulation results. Here, we have fabricated two types of micron-sized kites having internal angles of 72°–90°–108°–90° and 72°–99°–90°–99°, respectively, and we have experimentally studied their phase behavior in two-dimensional systems. Interestingly and in contrast to the Monte Carlo simulations, the experimental results show a phase sequence of isotropic fluid-hexagonal rotator crystal-square crystal as the area fraction ϕ A increases for both types of kites. The observed square crystal displays not only a quasi-long-range translational order but also (quasi-)long-range 4-fold bond- and molecular-orientational order; these characteristics confirm that tetratic order can emerge even in dense Brownian systems of rotationally asymmetric particles. A model based on local polymorphic configurations (LPCs) is proposed to understand the origin of the square lattice order in these dense kite systems. The results in this study provide a new route to realize custom-designed self-assembly of colloids by controlling LPCs.

Modification of surface morphology and lattice order in nanocrystalline ZnO thin films prepared by spin-coating sol–gel method

Modification of surface morphology and lattice order in nanocrystalline ZnO thin films prepared by spin-coating sol–gel method

Atomic-Resolution Cryogenic Scanning Transmission Electron Microscopy for Quantum Materials.

ConspectusThe rich physics permeating the phase diagrams of quantum materials have commanded the attention of the solid-state chemistry, materials science, and condensed-matter physics communities, sparking immense research into quantum phase transitions including superconducting, ferroic, and charge-order transitions. Many of these transitions occur at low temperatures and involve electronic, magnetic, or lattice order, which emerges on the atomic to mesoscopic scales. The complex interplay of these states and the heterogeneity that arises due to competition and intertwining of phases, however, is not fully understood and requires probes that capture ordering over multiple length scales down to the local atomic symmetries. Advances in scanning transmission electron microscopy (STEM) have enabled atomic-resolution imaging as well as mapping of functional picometer-scale atomic displacements inside materials. In this Account, we discuss our group's work to expand the reach of atomic-resolution STEM to cryogenic temperatures (cryo-STEM) to study quantum materials with focus on charge-ordered systems.Charge-ordered phases, in which electrons as well as the atomic lattice form periodic patterns that lift the translational symmetries of the crystal, are not only intertwined with superconductivity but also underlie other exotic electronic phenomena such as colossal magnetoresistance and metal-insulator transitions. The periodic lattice distortions (PLDs) modulate the positions of the crystal's nuclei, which can be readily probed by electron microscopy. In a set of examples, we demonstrate cryo-STEM as a powerful technique for probing local order, nanometer-scale heterogeneities, and topological defects in charge-ordered manganites and in transition metal dichalcogenide charge density wave (CDW) systems.With the nearly commensurate-to-commensurate CDW transition upon cooling in 1T-TaS2, we show that nanoscale lattice textures in CDW phases can be revealed through direct imaging. These early atomic-resolution results, however, also highlighted the need for improvements in cryo-STEM imaging, which led to a push to advance data collection and analysis for direct spatial mapping and quantification of PLDs. By introducing an image registration algorithm developed specifically to accommodate fast, low signal-to-noise image acquisitions of crystalline lattices, we address previous limitations due to sample drift in cryo-STEM experiments. This has enabled subangstrom cryo-STEM imaging with sufficient signal-to-noise to reveal the low temperature structure of 1T'-TaTe2. Furthermore, it allows mapping and quantification of PLD atomic displacements in the charge-ordered manganites Bi0.35Sr0.18Ca0.47MnO3 and Nd0.5Sr0.5MnO3 with picometer precision at ∼95 K to resolve not only distinct ordered phases (i.e., site- and bond-centered charge order) but also their nanoscale coexistence within the same sample.Atomic-resolution cryo-STEM opens new opportunities for understanding the microscopic underpinnings of quantum phases. In this Account, we focus on spatial mapping of lattice degrees of freedom in phases that are present at temperatures down to liquid nitrogen. Further advances in instrumentation are needed to expand the temperature range and to also enable atomic-resolution measurements that rely on weaker signals such as electron energy loss spectroscopy (EELS) for probing of electronic structure or 4D-STEM approaches to map electric and magnetic fields.

Germanene structure enhancement by adjacent insoluble domains of lead

Growth of Xene, referred to as the analog of graphene made of atoms other than carbon, with higher lattice quality and more intrinsic electronic structures, is an important challenge to the development of two-dimensional (2D) materials. We report an approach using Pb-atom deposition to striped-phase (SP) germanene grown on Ag(111) to trigger it to a quasifreestanding phase (QP). Using low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM), we demonstrate that the 2D monatomic Pb layer, instead of being on top, grows side-by-side with QP germanene, not only driving the SP-to-QP transition but further enhancing the lattice order of QP as revealed by the dramatic evolution of LEED-spot shape and uniform STM-imaged array of moir\'e patterns. Originally oriented at 30\ifmmode^\circ\else\textdegree\fi{} to Ag(111), the QP germanene transits first to a narrow distribution of rotations then to two sharp domains at \ifmmode\pm\else\textpm\fi{}3\ifmmode^\circ\else\textdegree\fi{} from 30\ifmmode^\circ\else\textdegree\fi{}, while the monoatomic Pb domains twist from \ifmmode\pm\else\textpm\fi{}4.3\ifmmode^\circ\else\textdegree\fi{} to \ifmmode\pm\else\textpm\fi{}9.5\ifmmode^\circ\else\textdegree\fi{} with respect to Ag(111). The analysis of higher-order coincidence for both layers on Ag(111) is in complete agreement with LEED results and reveals a picture of two insoluble monatomic layers driving each other to a more optimal configuration. Moreover, the corresponding density of states measured by scanning tunneling spectroscopy for quality-enhanced QP germanene exhibits a clear V-shape distribution at the energy \ensuremath{\sim}0.4 eV above Fermi level, indicating the Fermi-Dirac cone, which agrees with our density functional theory calculation.

Some Properties of Lattice Ordered Rings

Some Properties of Lattice Ordered Rings

Ferromagnetic strain glass and its physical properties

Ferromagnetic strain glass is a glassy phenomenon reported in the defects of doped Ni-Mn-Ga, Fe-Pd, and Fe-Ni-Cr ferromagnetic martensitic alloy systems recently. It is essentially a frozen state with coexisting short-range lattice strain order and long-range magnetic order. The basic structural unit of the ferromagnetic strain glass is the magnetic martensitic nanodomain. The reorientation energy barrier of these nanodomains is insignificant. They grow slowly across a wide temperature region in the parent phase matrix, and the modulus of the parent phase matrix and nanodomains shows an opposite temperature-dependent tendency. These transforming properties lead to the low-field-driven large magnetostriction and Elinvar effect. Therefore, ferromagnetic strain glass alloys have potentially important applications in microactuators or sensors and precision apparatuses. This paper introduces the macroscopic physical properties, microstructural characteristics, and functional effects of ferromagnetic strain glass. Through the phase diagram of the Ni- X -Mn-Ga ( X =Co, Fe) system, the formation of a ferromagnetic strain glass and its relationship with martensitic and premartensitic phases are clarified. Furthermore, the novel transformation behavior, i.e., the spontaneous martensitic transition of ferromagnetic strain glass in the phase boundary region between ferromagnetic martensite and ferromagnetic strain glass, is also introduced. The material design based on ferromagnetic strain glass is expected to bring new opportunities for the performance breakthrough and functionality development of magnetic materials.

Oxygen magnetic polarization, nodes in spin density, and zigzag spin order in oxides

Recent DFT calculations for Ba2CoO4 (BCO) and neutron scattering experiments for SrRuO3 (SRO) have shown that oxygen develops a magnetic polarization. Moreover, DFT calculations for these compounds also unveiled unexpected nodes in the spin density, both along Co-O and Ru-O. For BCO, the overall antiferromagnetic state in its triangular lattice contains unusual zigzag spin patterns. Here, using simple model calculations supplemented by DFT we explain and extend these results. We predict that ligands that in principle should be spinless, such as O$^{2-}$, will develop a net polarization when they act as electronic bridges between transition metal (TM) spins ferromagnetically ordered, regardless of the number of intermediate ligand atoms. The reason is the hybridization between atoms and mobility of the electrons with spins opposite to those of the closest TM atoms. Moreover, for bonds with TMs antiferromagnetically ordered, counterintuitively our calculations show that oxygens should also have a net magnetization for the super-super-exchange cases TM-O-O-TM while for only one oxygen, as in Cu-O-Cu, the O-polarization should cancel. Our simple model also allows us to explain the presence of nodes based on the antibonding character of the dominant singly occupied molecular orbitals along the TM-O bonds. Finally, the zigzag pattern order becomes the ground state mainly due to the influence of the Hubbard $U$, that creates the moments, in combination with a robust easy-axis anisotropy that suppresses the competing 120$^{\circ}$ degree antiferromagnetic order of a triangular lattice. Our predictions are generic and should be applicable to any other compound with characteristics similar to those of BCO and SRO.

Theoretical Study of Tunable Optical Resonators in Periodic and Quasiperiodic One-Dimensional Photonic Structures Incorporating a Nematic Liquid Crystal

In this work, the transfer matrix method (TMM) is employed to investigate the optical properties of one-dimensional periodic and quasiperiodic photonic crystals containing nematic liquid crystal (NLC) layers. This structure is expressed as (ABC)J(CBA)J and made of alternated layers of isotropic dielectrics SiO2 (A), BGO (B) and nematic liquid crystal (C). The simulation study shows that the proposed ternary configuration exhibits tunable defect mode within the photonic band gap (PBG) that can be manipulated by adjusting the thicknesses of NLC layers in order of the periodic lattice. In addition, the optimized structure permits for strong confinement light giving rise to an optical microcavity. The application of an applied voltage into NLC layers enables improving the sensitivity by guiding the local defect mode. It has been also shown that by applying quasiperiodic inflation according to Rudin Shapiro Sequence (RSS) scheme to main periodic structure, several tunable resonant modes appear within the PBG. The presence of such sharp resonant peaks reflects that the quasiperiodic NLC-based structure behaves like multiple microcavites with strong light-matter coupling.

Correction to “Effects of Lattice Evolution and Ordering on the Microwave Dielectric Properties of Tin-Modified Li3Mg2NbO6-Based Ceramics”

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “Effects of Lattice Evolution and Ordering on the Microwave Dielectric Properties of Tin-Modified Li3Mg2NbO6-Based Ceramics”Xing ZhangXing ZhangMore by Xing Zhang, Xiao ZhangXiao ZhangMore by Xiao Zhang, Zixuan FangZixuan FangMore by Zixuan Fang, Zhe XiongZhe XiongMore by Zhe Xiong, Hongyu YangHongyu YangMore by Hongyu Yanghttp://orcid.org/0000-0002-5894-1693, Shuren ZhangShuren ZhangMore by Shuren Zhang, and Bin Tang*Bin TangMore by Bin Tanghttp://orcid.org/0000-0002-3851-2330Cite this: J. Phys. Chem. C 2021, 125, 18, 10173Publication Date (Web):April 28, 2021Publication History Published online28 April 2021Published inissue 13 May 2021https://doi.org/10.1021/acs.jpcc.1c03439Copyright © 2021 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views371Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (688 KB) Get e-Alerts Get e-Alerts

Quantum Phase Transition at Nonzero Doping in a Random t-J Model.

We present exact diagonalization results on finite clusters of a t-J model of spin-1/2 electrons with random all-to-all hopping and exchange interactions. We argue that such random models capture qualitatively the strong local correlations needed to describe the cuprates and related compounds, while avoiding lattice space group symmetry breaking orders. The previously known spin glass ordered phase in the insulator at doping p=0 extends to a metallic spin glass phase up to a transition p=p_{c}≈1/3. The dynamic spin susceptibility shows signatures of the spectrum of the Sachdev-Ye-Kitaev models near p_{c}. We also find signs of the phase transition in the entropy, entanglement entropy, and compressibility, all of which exhibit a maximum near p_{c}. The electron energy distribution function in the metallic phase is consistent with a disordered extension of the Luttinger-volume Fermi surface for p>p_{c}, while this breaks down for p<p_{c}.

Synchronous RNA conformational changes trigger ordered phase transitions in crystals

Time-resolved studies of biomacromolecular crystals have been limited to systems involving only minute conformational changes within the same lattice. Ligand-induced changes greater than several angstroms, however, are likely to result in solid-solid phase transitions, which require a detailed understanding of the mechanistic interplay between conformational and lattice transitions. Here we report the synchronous behavior of the adenine riboswitch aptamer RNA in crystal during ligand-triggered isothermal phase transitions. Direct visualization using polarized video microscopy and atomic force microscopy shows that the RNA molecules undergo cooperative rearrangements that maintain lattice order, whose cell parameters change distinctly as a function of time. The bulk lattice order throughout the transition is further supported by time-resolved diffraction data from crystals using an X-ray free electron laser. The synchronous molecular rearrangements in crystal provide the physical basis for studying large conformational changes using time-resolved crystallography and micro/nanocrystals.

Electronic reconstruction forming a C2-symmetric Dirac semimetal in Ca3Ru2O7

Electronic band structures in solids stem from a periodic potential reflecting the structure of either the crystal lattice or electronic order. In the stoichiometric ruthenate Ca3Ru2O7, numerous Fermi surface-sensitive probes indicate a low-temperature electronic reconstruction. Yet, the causality and the reconstructed band structure remain unsolved. Here, we show by angle-resolved photoemission spectroscopy, how in Ca3Ru2O7 a C2-symmetric massive Dirac semimetal is realized through a Brillouin-zone preserving electronic reconstruction. This Dirac semimetal emerges in a two-stage transition upon cooling. The Dirac point and band velocities are consistent with constraints set by quantum oscillation, thermodynamic, and transport experiments, suggesting that the complete Fermi surface is resolved. The reconstructed structure—incompatible with translational-symmetry-breaking density waves—serves as an important test for band structure calculations of correlated electron systems.

Properties of Generalised Lattice Ordered Groups

A partially ordered group (po-group) is said to be a generalised lattice ordered group (gl-group) if the underlying poset is a generalised lattice. This paper is a study of some properties of finite subsets of a generalised lattice ordered group (gl-group). Finally obtained a lattice ordered group (l-group) from the given interally closed gl-group and concluded that every integrally closed gl-group is distributive.

Polycrystalline Indium Gallium Tin Oxide Thin-Film Transistors With High Mobility Exceeding 100 cm2/Vs

This letter reports the fabrication of high performance polycrystalline InGaSnO (IGTO) thin-film transistors (TFTs) at a low temperature of 400 °C. The microstructure of IGTO films was analyzed using X-ray diffraction and high-resolution transmission electron microscopy. The fabricated polycrystalline IGTO TFTs exhibited an unexpected high mobility of 116.5 cm2/Vs, threshold voltage of 0.47 V, low subthreshold gate swing of 134 mV/decade, and ${I}_{ON/OFF}$ ratio of $> 1\times 10^{9}$ . Moreover, the stable behavior against external gate bias stress was observed for crystalline IGTO TFTs, which was attributed to the high degree of metal-oxygen lattice ordering.

Nanometric skyrmion lattice from anisotropic exchange interactions in a centrosymmetric host

Skyrmion formation in centrosymmetric magnets without Dzyaloshinskii–Moriya interactions was originally predicted from unbiased numerical techniques. However, no attempt has yet been made, by comparison to a real material, to determine the salient interaction terms and model parameters driving spin-vortex formation. We identify a Hamiltonian with anisotropic exchange couplings, local ion anisotropy, and four-spin interactions, which is generally applicable to this class of compounds. In the representative system Gd3Ru4Al12, anisotropic exchange drives a fragile balance between helical, skyrmion lattice (SkL), and transverse conical (cycloidal) orders. The model is severely constrained by the experimentally observed collapse of the SkL with a small in-plane magnetic field. For the zero-field helical state, we further anticipate that spins can be easily rotated out of the spiral plane by a tilted magnetic field or applied current.

Electric-field-induced modulation of thermal conductivity in poly(vinylidene fluoride)

Phonon engineering focuses on heat transport modulation in atomic-scale. Different from reported methods, it is shown that electric field can also modulate heat transport in ferroelectric polymers, poly(vinylidene fluoride), by both simulation and measurement. Interestingly, the thermal conductivities of poly(vinylidene fluoride) array can be enhanced by a factor of 3.25 along the polarization direction by simulation. The thermal conductivities of semi-crystalline poly(vinylidene fluoride) film can be also enhanced by a factor of 1.5 which is shown by both simulation and measurement. The mechanism is analyzed by morphology and phonon properties. It is found that the enhancement arises from the higher inter-chain lattice order, stronger inter-chain interaction, higher phonon group velocity and suppressed phonon scattering. This study offers a new modulation strategy with quick response and without fillers. Poled by electric field, thermal conductivity of poly(vinylidene fluoride) (PVDF) can be increased, which is proved by both simulations and experiments. The study offers a brand new strategy to modulate thermal conductivity. • A new strategy to modulate thermal conductivity of polymer with electric field is proposed and proved. • Thermal conductivities in poly(vinylidene fluoride) can be modulated without sacrificing other mechanical properties. • Modulation with electric field is in situ, flexible control, quick response and low energy consumption. • A detailed analysis on the mechanism of thermal conductivity enhancement is presented.

Characterization and Molecular Docking of Kaolin Based Cellulosic Film for Extending Ophthalmic Drug Delivery

Ophthalmic delivery of dexamethasone can control inflammation and also some forms of uveitis. But it is effective therapeutically over a short period of time and frequent instillation is required. hydroxypropyl methylcellulose matrix films containing dexamethasone were prepared by casting method in presence and absence of particulate kaolin for extending ophthalmic drug delivery. Fourier-transform infrared spectroscopy confirmed the complexation of dexamethasone and kaolin in the film via formation of hydrogen bond and the observed shouldering at 1032 cm-1 increased with corresponding higher amount of kaolin binding. Differential scanning calorimetry thermogram resulted in almost complete amorphization of dexamethasone in the film. X-ray diffractogram demonstrated almost disappearance of kaolinite diffraction and the reduced order of dexamethasone crystal lattice in all the film formulations. Submicrons, tubular and nano-fibrous morphology of the kaolin and drug particles were seen in the scanning electron microscope images of the film. Relatively extended diffusion controlled drug release and ophthalmic permeation behavior were observed with the increase of kaolin loading in the film. Stable complex facilitated the sustained ophthalmic delivery of dexamethasone and prolonged anti-inflammatory activity. Molecular docking study also revealed the complex formation of dexamethasone with kaolin and hydroxypropyl methyl cellulose to understand the fitting and stable configuration of drug-carrier interaction. Kaolin-based hydroxypropyl methyl cellulose hydrogel film containing dexamethasone as a model drug can enhance the corneal residence time for anti-inflammation for an extended period of time.

Atomic insight into spin, charge and lattice modulations at SrFeO3-x/SrTiO3 interfaces.

Novel phenomena and functionalities at interfaces of oxide heterostructures are currently of great interest in a wide range of applications. At such interfaces, charge, spin, orbital and lattice ordering coexist and correlate closely, contributing to rich functional responses. By using atomically resolved imaging and spectroscopy techniques, we investigated magnetic behaviors and structural modulation at the SrFeO3-x/SrTiO3 interface. Fe/Ti element intermixing and oxygen vacancies occurred across a few unit cells at the interface. Furthermore, antiferromagnetic spin ordering of Fe with different valence states in the interface of SrFeO3-x/SrTiO3 induced uncompensated magnetic moments. Compared to the SrFeO3-x/La0.3Sr0.7Al0.65Ta0.35O3 heterojunction, the variations of charge and lattice order parameters at the SrFeO3-x/SrTiO3 interfaces were also determined by advanced electron microscopy, which provided a good understanding of the physical origin of disparate macroscopic magnetic properties, further investigated by magnetometer measurements and X-ray magnetic circular dichroism (XMCD) spectra. These studies provide comprehensive insight into the interfacial modulation of ferrite oxide, which may be useful for designing future devices in oxide electronics.

On Involution Lattice Ordered Semigroups

A $$poe$$ -semigroup $$(S,\cdot,\leq)$$ equipped with an order preserving involution ‘‘ $$*$$ ’’ is called an involution ordered semigroup. An $$le$$ -semigroup is a lattice ordered semigroup possessing a greatest element. The concepts of $$*$$ -regularity, $$*$$ -intra-regularity, $$*$$ -bi-ideal element and $$*$$ -quasi-ideal element in this type of semigroups have been introduced and, using the right and left ideal elements, relationships among them are given. The $$*$$ -regular (resp. $$*$$ -intra-regular) $$poe$$ -semigroups are regular (resp. intra-regular). It is shown, among others, that in an involution $$*$$ -regular $$\vee e$$ -semigroup every $$*$$ -bi-ideal element can be represented as the product of a right and a left ideal element. Necessary and sufficient conditions are given under which an involution $$le$$ -semigroup is $$*$$ -regular, regular, $$*$$ -intra-regular or intra-regular. An involution $$poe$$ -semigroup $$S$$ is $$*$$ -intra-regular if and only if the ideal elements of $$S$$ are $$*$$ -semiprime; and an analogous result for involution $$*$$ -left or $$*$$ -right $$poe$$ -semigroups also holds. It is also shown that in an involution $$*$$ -intra-regular $$poe$$ -semigroup $$S$$ , the filter generated by an element $$x$$ of $$S$$ has a very simple form that is useful for the investigation. As a consequence, in this type of semigroups the element $$ex^{*}e$$ is contained in the $$(x^{*})_{\mathcal{N}}$$ -class (for any $$x$$ ) and it is the greatest element of the class $$(x)_{\mathcal{N}}$$ .

Some Properties of Lattice Ordered Rings

Some Properties of Lattice Ordered Rings