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The combined influence of spin–orbit coupling and spatial inversion asymmetry leads to an enhancement of electronic properties, including Rashba spin-splittings as well as spin Hall effect. Recent research has shown the possibility to create two-dimensional Janus materials with inherent structural asymmetry. In this work, the structural stability, piezoelectricity, electronic properties, and intrinsic spin Hall conductivity of quintuple-layer atomic Janus Sb2XSX' (X, X' = S, Se, Te; X ≠ X') monolayers are investigated using first-principles calculations within the framework of density functional theory. They demonstrate relatively high in-plane piezoelectric coefficients ( d 22) and also possess out-of-plane piezoelectric coefficients ( d 31), which is due to the breaking of inversion symmetry in the crystal structure with the space group P3m1. Large Rashba parameters are obtained in Janus Sb2XSX' monolayers, especially high for Sb 2 S 2 Te (1.62 eV Å) and Sb 2 SeSTe (1.33 eV Å) due to strong spin–orbit coupling. Moreover, Rashba-like spin-splitting is also observed in the edge-states as well, which is highest for Sb 2 SeSTe with 2.17 eV Å. Furthermore, Sb 2 S 2 Te and Sb 2 SeSTe monolayers reveal a significantly high Berry curvature (65.59 and 61.05 Bohr 2), spin Berry curvature (− 118.4 and − 120.6 Bohr 2), and spin Hall conductivity (1.8 and 1.6 e 2 /h). Our results suggest that Janus Sb 2 S 2 Te and Sb 2 SeSTe monolayers could be an excellent platform for multifunctional electronic applications. [ABSTRACT FROM AUTHOR]

Brillouin light scattering is a versatile measurement technique of the dispersion of bulk acoustic phonons in amorphous and crystalline solids. It allows contactless and non-destructive characterization of the relevant material tensors of optically transparent materials, provided that the optical refraction indices, and in addition the dielectric tensor for piezoelectric materials, are known beforehand. The complete estimation of the anisotropic material tensors is often performed using many different crystal orientations, and hence different samples of the same crystal. In this paper, we consider the problem of measuring those tensors using a single sample of an anisotropic single crystal with trigonal symmetry. A complete measurement requires sufficient experimental diversity in the phonon wavevectors when sampling the phonon velocity surfaces, hence the consideration of a large number of directions away from crystallographic axes. We estimate all six independent elastic constants of non-piezoelectric sapphire ( 3 ¯ m point group) with a single X-cut wafer and the six independent elastic constants together with the four independent piezoelectric constants of piezoelectric lithium niobate (3 m point group) with a single Y-cut wafer. The estimated tensors are in close agreement with those reported in the literature based on resonant ultrasonic techniques. [ABSTRACT FROM AUTHOR]

The all-temperature magnon (ATM) theory [Datta and A. Panda, J. Phys. Condens. Matter 21, 336003 (2009)] has been used to analyze the temperature dependence of magnetization and internal energy components of a mono-domain ferromagnetic solid. One impact of the ATM formulation is that calculated critical exponents are in better agreement with experiments than their counterparts from mean-field and critical phenomenon theories. These exponents can vary from one ferromagnet to another of similar symmetry and dimensionality but differing in spin and can be field-dependent. The ATM finding is that exponent β depends on spin and increases as T approaches TC, whereas the exponent γ is weakly dependent on spin and the applied field but relies on crystal symmetry. The main thrust of the present work has been to derive the thermally averaged spin-center force constants in terms of the baseline related (solid) and exchange-cum-field mediated (magnetic) components and to formulate phonon frequencies and their modifications by magnon–phonon coupling. The derived expressions are suitable for correct quantum chemical evaluation. A detailed calculation on different spin configurations at varying geometries is still hardly possible and beyond the scope of the present work that emphasizes the correctness of formulas and has the significance of explaining properties. The phonon frequency shift due to lattice expansion is always negative. It is also clarified that frequency modification by the magnon–phonon interaction is negative for certain phonon branches near TC, and the ratio of frequency modification and phonon frequency is approximately proportional to the ratio of curvatures of involved energy surfaces. [ABSTRACT FROM AUTHOR]

In this study, the effect of elastic biaxial strain on electronic structure and the anomalous Hall conductivity (AHC) of α‐Fe has been systematically studied by using the combination of a first principles calculation with the tight binding method through the Wannier function. It is found that applying strain in cubic structure of α‐Fe results in the reduction of crystal symmetry and gives the modification on the bands near Fermi level, which causes a significant change in the AHC of strained systems. The AHC of strained α‐Fe is found to be sensitive with applying strain, which shows the large enhancement of AHC at +2% tensile strain with AHC value is up to 929 Ω−1 cm−1 (increases more than 30%) compared with the unstrained one, while slightly reduces when applying compressive strain. The modification of AHC is found to be related to the change of Berry curvature contributed from the spin orbit coupling (SOC) induced energy gap near Fermi level. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In recent years, dislocation‐tuned functionalized ceramics have become one of the focal points of modern materials research due to their outstanding properties. These range from improved electrical conductivity and ferroelectric properties to dislocation‐enhanced toughening and superconductivity, caused by local strain fields. The aim of this work is to investigate the dislocation‐induced structural changes in single‐crystal KNbO3 by micro‐Raman spectroscopy. Dislocation‐rich regions with tailored densities have been generated using the Brinell indenter scratching method. The influence of the dislocations on the single‐crystal structure can be observed in the Raman spectra. The activation of additional Raman modes is observed, which does not occur in regions of low dislocation density. This observation is confirmed by DFT calculations of vibrational modes and is attributed to a reduction in the crystal symmetry due to increased defect densities in plastically deformed KNbO3. In addition, an increase in compressive stress at higher dislocation densities can be demonstrated by a blueshift in Raman mode positions. [ABSTRACT FROM AUTHOR]

Resonant inelastic X-ray scattering (RIXS) has played a pivotal role in advancing our understanding of spin-orbit physics in 5d transition metal materials. The progress in RIXS techniques has closely paralleled improvements in energy resolution, which have enabled the study of very low-lying excitations and led to the discovery of numerous new phenomena with significant scientific and technological implications. The multi-bend achromat (MBA) lattice upgrade of third-generation synchrotron sources, such as the Advanced Photon Source (APS), heralds a transformative era by introducing enhancements in brilliance and emittance. These advancements provide an opportunity to push the boundaries of RIXS techniques, meeting the challenges at the research frontiers of material science. This article aims to highlight key instrumental and technical advancements that enable the achievement of meV resolution in RIXS and discuss the impact of such high-resolution RIXS on exploring spin-orbit physics in 5d transition metal materials. [ABSTRACT FROM AUTHOR]

How to break the C═O bond and reduce the energy barrier of *COOH formation is the key to triggering the photocatalytic CO2 reduction (PCR) reaction and subsequent proton‐electron processes, which is as important as overcoming high recombination rate of photocarriers. In order to solve this issue, the symmetric structure of CuS/TiO2 is destroyed by S vacancy and Al doping (denoted as Al‐CuS/TiO2), which significantly expands the electron localization range and promotes the cis‐coordination splitting of Cu 3d orbits. The experimental results show that the CO yield selectivity of ≈90.68% and yield of ≈335.68 µmol·g−1·h−1 on Al‐CuS/TiO2. The redistribution of Cu electron states in specific d/s/p orbitals increases the adsorption of CO2 and reduces the reaction energy barrier of *COOH intermediates, while effectively breaking the C═O bond. Doped Al atoms also serve as adsorption sites for H2O molecules, effectively interleaving the competition with photocatalytic CO2 reduction at the Cu sites is effectively staggered. This study provides a new approach to reduce the energy barrier of *COOH formation and to accelerate the photocarrier migration by destroying local symmetry to adjust the crystal structure, which is important for further improving the activity and selectivity of PCR. [ABSTRACT FROM AUTHOR]

In the classical model, ferroelectricity is associated with small ion displacements from paraelectric phases with high symmetry, and ferroelectric crystals must adopt one of the ten polar point groups with low symmetry according to Neumann's principle. In this work, it is proposed that this conclusion is based on perfect bulk crystals without taking the boundaries into account. First‐principles evidence shows that ferroelectric polarizations may also be formed in some non‐polar point groups as the edges generally break the crystal symmetry. Meanwhile, such polarizations can be maintained at macroscale and are switchable when the transition between multiple equivalent states with high symmetry can be realized via long ion displacements， essentially akin to ion conductors. For example, the switching barriers can be much reduced in sliding ferroelectric bilayer systems or ionic compounds with covalent‐like directionality. Such unconventional ferroelectricity can be attributed to the boundaries and long ion displacements, and its existence in several systems like CuCrS2 is supported by experimental observations. It may explain a series of unclarified phenomena reported previously as well as significantly expand the scope of ferroelectrics, especially those with high polarizations induced by long ion displacements. [ABSTRACT FROM AUTHOR]

How to break the C═O bond and reduce the energy barrier of *COOH formation is the key to triggering the photocatalytic CO2 reduction (PCR) reaction and subsequent proton‐electron processes, which is as important as overcoming high recombination rate of photocarriers. In order to solve this issue, the symmetric structure of CuS/TiO2 is destroyed by S vacancy and Al doping (denoted as Al‐CuS/TiO2), which significantly expands the electron localization range and promotes the cis‐coordination splitting of Cu 3d orbits. The experimental results show that the CO yield selectivity of ≈90.68% and yield of ≈335.68 µmol·g−1·h−1 on Al‐CuS/TiO2. The redistribution of Cu electron states in specific d/s/p orbitals increases the adsorption of CO2 and reduces the reaction energy barrier of *COOH intermediates, while effectively breaking the C═O bond. Doped Al atoms also serve as adsorption sites for H2O molecules, effectively interleaving the competition with photocatalytic CO2 reduction at the Cu sites is effectively staggered. This study provides a new approach to reduce the energy barrier of *COOH formation and to accelerate the photocarrier migration by destroying local symmetry to adjust the crystal structure, which is important for further improving the activity and selectivity of PCR. [ABSTRACT FROM AUTHOR]

It is well known that the properties of a crystal evolve as it increases in size from a single atomic plane to that of the bulk. Such size‐dependent transitions can stem from many different origins and depend on minute changes to crystal bonding and composition. A model example is that of LaCoO3, which is non‐magnetic in the bulk but can display ferromagnetism at the nanoscale. Here, the evolution of structure‐property relationships is studied in the LaCoO3−δ/SrTiO3 (001) system as the thickness of LaCoO3−δ is increased from a single plane to 10 unit cells. In situ synchrotron X‐ray studies are performed during and post‐deposition to probe changes in the interactions between structure, stoichiometry, and magnetic behavior. Structural quantification indicates that the oxygen octahedral rotation pattern evolves with thickness, due to inherent differences in crystal symmetry between the film and substrate. The change in rotation modifies the required energy barrier for the spin state transition via the Co–O bond length and Co–O–Co bond angle, affecting the appearance of ferromagnetism. Our results highlight the contributions of high spin Co2+ and/or high spin Co3+ to respective weak and robust ferromagnetism and the evolution of properties with size in ultrathin LaCoO3−δ heterostructures. [ABSTRACT FROM AUTHOR]

Magneto-electric effect, i.e. an appearance of magnetisation induced by electric current, is allowed by symmetry in metals with crystal structure without space inversion. The microscopic origin of this effect is spin–orbit coupling of electrons with a non-centrosymmetric crystal lattice lifting spin degeneracy of electron energy and mixing spin and orbital degrees of freedom. The presented here calculation of magnetisation induced by current is based on the application of kinetic equation for the matrix distribution function of electrons occupying the states in two bands split by the spin–orbit interaction. [ABSTRACT FROM AUTHOR]

This study investigates the pressure-dependent thermal and mechanical properties of solid bromine through density functional theory (DFT) calculations used in conjunction with the quasi-harmonic approximation (QHA). At ambient pressure, bromine crystallizes as a molecular crystal of Cmca symmetry. Previous studies have indicated that upon compression, this polymorph should undergo a bandgap closure at 80 GPa followed by a phase transition to a nonmolecular phase at 90 GPa. By employing QHA, we model the lattice vibrations and calculate the free energy, thermal expansion, and specific heat capacities of solid molecular bromine over a temperature range from 0 to 1000 K and pressures up to 90 GPa. Furthermore, mechanical properties such as bulk modulus and elastic constants are also analyzed. The results reveal the significant impact that pressure has on the thermal properties, mechanical stability, and dynamical stability of a molecular crystal. These findings contribute to a deeper understanding of such systems under extreme conditions, potentially guiding future experimental and theoretical investigations. [ABSTRACT FROM AUTHOR]

Morphology‐controlled Cs2SbBr6 crystals are synthesized by Bi‐ and Ag‐substitution of the precursor solution. X‐ray diffraction (XRD) together with Raman spectroscopy confirms the lattice tilting and symmetry changes with the dominant appearance of higher index facets by Bi substitution. Ag substitution does not induce crystal symmetry changes in the Cs2BBr6 (B = Sb or Bi) phase, but results in highly defective structures hindering the formation of a smooth surface during the crystal growth. Successful substitution of Bi and limited substitution of Ag into Cs2SbBr6 is also confirmed by energy dispersive X‐ray spectroscopy (EDX). This research provides design principles and practical examples of how to control the morphology of Cs2SbBr6 crystals with structural defects and multiphase formation. [ABSTRACT FROM AUTHOR]

An exhaustive search for missing symmetry was performed for 223076 entries in the ICSD (2023‐2 release). Approximately 0.65% of them can be described with higher symmetry than reported. Out of the identified noncentrosymmetric entries, ∼74% can be described by centrosymmetric space groups; this has implications for compatible physical properties. It is proposed that the information on the correct space group is included in the ICSD. [ABSTRACT FROM AUTHOR]

The study focused on the nitrilo‐tris‐(methylene phosphonate) [K2ntpH4]2 and [(K1−yTly)2ntpH4]2 complexes, which are a series of isovalent substitutions. The crystals of [K2ntpH4]2 are monoclinic and belong to the space group of symmetry P21/c with Z=4. When thallium substitutes potassium, the molecular structure remains the same, but the symmetry of the crystal packing changes to a triclinic system, space group of symmetry P1‾ ${\bar{1}}$ , with Z=2. One coordination polyhedra maintains an isometric configuration, while the other undergoes significant distortions. Polarization‐selective coordination is observed, where the thallium(I) ion, which is easily polarizable, populates the highly distorted polyhedron. The low polarizable potassium ion populates the weakly distorted one. The crystal is formed with an average thallium fraction higher than the initial aqueous solution. This suggests that replacing potassium ions in the complex with thallium ions is energetically favourable. It could explain why thallium is toxic to intracellular enzymes and carriers of genetic information. The isovalent substitution of potassium made it possible to observe the step‐by‐step formation of a super‐strong hydrogen bond, a phenomenon that is rarely detected under normal conditions. The O...O interatomic distance in the hydrogen bond decreases gradually from 2.55 Å for [K2ntpH4]2 to 2.474 Å for [Tl2ntpH4]2. [ABSTRACT FROM AUTHOR]

Recently a large variety of non‐collinear spin textures have been revealed in various crystals with different symmetry groups. Of particular interest are crystals with D2d symmetry that exhibit a complex variety of stable and metastable spin textures that includes antiskyrmions, elliptical Bloch‐skyrmions, fractional‐antiskyrmions, fractional Bloch‐skyrmions, and type‐II trivial‐bubbles. The observation of these structures necessitates their stabilization via magnetic field and temperature protocols which demands a thorough understanding of their creation, transformation, and collapse dynamics. Utilizing the real‐space imaging capabilities of Lorentz transmission electron microscopy, the generation and annihilation of diverse spin textures in a single D2d Heusler compound are demonstrated. It is showed that antiskyrmions and elliptical Bloch‐skyrmions can be deformed into more elaborate elongated magnetic nano‐objects through a collapse mechanism. Their elongation is governed by the intrinsic antisymmetric Dzyaloshinskii‐Moriya vector exchange interaction and dipolar energy present in the system. Furthermore, antiskyrmions are found to be metastable at all temperatures on field‐cooling, while a topological phase transformation from elliptical Bloch‐skyrmions to antiskyrmions rather takes places on field‐heating. These results are corroborated by micromagnetic simulations and demonstrate the efficient manipulation of different spin textures in a D2d compound by varying field and temperature protocols and represents a critical step toward the application of magnetic skyrmions. [ABSTRACT FROM AUTHOR]

Ceria has attracted a lot of interest in scientific community due to its several technological uses. During this study, composite hydroxide-mediated method was used to prepare nanocubes of undoped and doped ceria. The prepared materials were characterized using a number of analytical techniques including room temperature powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) theory, and UV–Visible spectroscopy to investigate the structural, morphological, optical and photocatalytic properties. No impurity phases were observed from the XRD revealing face centred cubic (FCC) crystal symmetry of the undoped and doped ceria. The formation of nanocubes was confirmed by SEM. Pore sizes in the range of 24.9–29 mm were revealed by BET analysis. A gradual increase in photodegradation efficiency with an increase in irradiation time was seen for the doped samples compared to undoped ceria, showing suitability for photocatalytic applications. An increase in defect concentrations especially for Sr2+ doped samples indicated by the quantitative analysis of Raman spectra reveals potential for electrolytic applications in fuel cells provided necessary conductivity and long-term performance testing would need to be done. [ABSTRACT FROM AUTHOR]

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Research on intragranular acicular ferrite inclusions has demonstrated that high-melting-point oxide MgAl2O4 cores and composite inclusions precipitated by Ti2O3 adhesion can be used as effective nucleation particles in oxide metallurgy. However, the microscopic mechanism underlying this adsorption behavior remains unclear. Hence, in this study, the adsorption and polymerization mechanisms of Ti2O3 on the MgAl2O4(100)Mg- and MgAl2O4(111)O3(Mg)-terminal surfaces in steel were studied using first-principles calculations based on density functional theory. The calculation based on the first principles of DFT and performed by the CASTEP code under plane wave basis set. The exchange correlation energy and correlation effects were described by generalized gradient approximation (GGA) using the Perdew–Burke–Ernzerhof (PBE) function. Spin polarization was considered in all calculation. Ultrasoft pseudopotentials (USPP) was employed to describe the electron-ion interactions. The energy cutoff for the plane wave basis was set at 620 eV in the current work. For the Brillouin zone sampling, we carried out 3 × 3 × 3 k-points mesh for MgAl2O4 bulk using the method of Monkhorst-Pack. A vacuum layer of 20.0 Å is added above the top surface of MgAl2O4 to eliminate the interaction of the normal periodic repetition of the surfaces. In all the surface calculations, the use of symmetry in bulk crystal was failed and k-point grids is set to 3 × 3 × 1. The results of this study revealed that when the most stable adsorption positions of Ti2O3 on the surface of MgAl2O4(100)Mg- and MgAl2O4(111)O3(Mg)-terminal are located at TAl and FMg, the adsorption energy is the highest and the most stable. The most stable adsorption configurations are located on vertical and parallel (P1) surfaces. Through comparative analysis, the best surface for Ti2O3 adsorption was found to be the MgAl2O4(111)O3(Mg)-terminal surface, and the adsorption behavior mainly occurred on the first layer of atoms on the surface. The best adsorption configuration was P1, and the best adsorption mode occurred when Ti2O3 formed three rings connected in pairs with the surface and embedded in the surface of the MgAl2O4(111)O3(Mg)-terminal. This study provides insights into the adsorption polymerization mechanisms of MgAl2O4–Ti2O3 complex inclusions in steel that could facilitate the fabrication of novel low-melting-point oxides and sulfides. [ABSTRACT FROM AUTHOR]

Materials exhibiting a spontaneous reversal of spin chirality have the potential to drive the widespread adoption of chiral magnets in spintronic devices. Unlike the majority of chiral magnets that require the application of an external field to reverse the spin chirality, we observe the spin chirality to spontaneously reverse in the topological magnet EuAl4. Using resonant elastic x-ray scattering we demonstrate that all four magnetic phases in EuAl4 are single-k, where the first two magnetic phases are characterized by spin density wave order and the last two by helical spin order. A single spin chirality was stabilised across the 1mm2 sample, and the reversal of spin chirality occurred whilst maintaining a helical magnetic structure. At the onset of the helical magnetism, the crystal symmetry lowers to a chiral monoclinic space group, explaining the asymmetry in the chiral spin order, and establishing a mechanism by which the spin chirality could reverse via magnetostructural coupling. The reversal of spin chirality in the absence of any externally applied field would substantially broaden the use of chiral magnets for applications in spintronic devices. In this manuscript the authors demonstrate the spontaneous reversal of spin chirality in the topological magnet EuAl4 using resonant elastic x-ray scattering. [ABSTRACT FROM AUTHOR]

Materials exhibiting a spontaneous reversal of spin chirality have the potential to drive the widespread adoption of chiral magnets in spintronic devices. Unlike the majority of chiral magnets that require the application of an external field to reverse the spin chirality, we observe the spin chirality to spontaneously reverse in the topological magnet EuAl4. Using resonant elastic x-ray scattering we demonstrate that all four magnetic phases in EuAl4 are single-k, where the first two magnetic phases are characterized by spin density wave order and the last two by helical spin order. A single spin chirality was stabilised across the 1mm2 sample, and the reversal of spin chirality occurred whilst maintaining a helical magnetic structure. At the onset of the helical magnetism, the crystal symmetry lowers to a chiral monoclinic space group, explaining the asymmetry in the chiral spin order, and establishing a mechanism by which the spin chirality could reverse via magnetostructural coupling. The reversal of spin chirality in the absence of any externally applied field would substantially broaden the use of chiral magnets for applications in spintronic devices. In this manuscript the authors demonstrate the spontaneous reversal of spin chirality in the topological magnet EuAl4 using resonant elastic x-ray scattering. [ABSTRACT FROM AUTHOR]

In this study, the propagation of plane waves in the lanthanum gallium tantalate (langatate, LGT) single crystals is investigated. Moreover, the flight time of different waves in the LGT rectangular parallelepiped sample is measured using the ultrasonic pulse‐echo (UPE) technique, and the elastic constants of the LGT sample are determined. The experimental results clearly show echoes corresponding to the longitudinal and transverse waves along the x‐axis. The waves along the z‐axis have a similar property. However, the waves along the y‐axis are more complex than those along the x‐ and z‐axes. The echoes corresponding to the quasi‐longitudinal waves along the y‐axis are clear, but those corresponding to the transverse and quasi‐transverse waves along the y‐axis are not. The elastic constant can be accurately determined if the wave echoes corresponding to this constant propagate without distinct distortion and are clear; otherwise, it may be impossible to accurately determine the constant using UPE. All elastic constants cijE$c_{ij}^{\mathrm{E}}$ except c13E$c_{13}^{\mathrm{E}}$ of the LGT single crystals can be determined using UPE from one sample. This study uses UPE to provide a reference for the characterization of elastic constants of piezoelectric crystals with 32 symmetry from one sample. [ABSTRACT FROM AUTHOR]

Local symmetry of crystal field is crucial for optical temperature sensitivity that based on the thermal couple levels of rare earth ions. In this work, Lu3+ ions were introduced to alter the local environment of Er3+ ions in oxyfluoride glass-ceramics. X-ray diffraction patterns and transmission electron microscope images show that Y 5 O 4 F 7 nanocrystals are precipitated in glass-ceramics. Incorporation of rare-earth ions into the Y 5 O 4 F 7 nanocrystals is confirmed by absorption and electron energy loss spectra. The Judd-Ofelt (J-O) theory analysis reveals that local symmetry of the crystal field around Er3+ decreasing due to Lu3+ co-doping. Temperature sensing property of the Y 5 O 4 F 7 : Er3+/Yb3+/Lu3+ nanocrystal incorporated glass-ceramic was investigated, and the optimal relative temperature sensitivity S R reaches 1.50 % K−1 in 0.25 mol.% Lu3+ doped specimen. Results show that the moderate addition of Lu3+ can improve the temperature sensitivity of glass-ceramic containing Y 5 O 4 F 7 :Er3+/Yb3+ nanocrystals, which provide a promising avenue for optical temperature sensing. [ABSTRACT FROM AUTHOR]

Higher-order topological phases in non-Hermitian photonics revolutionize the understanding of wave propagation and modulation, which lead to hierarchical states in open systems. However, intrinsic insulating properties endorsed by the lattice symmetry of photonic crystals fundamentally confine the robust transport only at explicit system boundaries, letting alone the flexible reconfiguration in hierarchical states at arbitrary positions. Here, we report a dynamic topological platform for creating the reconfigurable hierarchical bound states in heat transport systems and observe the robust and nonlocalized higher-order states in both the real-and imaginary-valued bands. Our experiments showcase that the hierarchical features of zero-dimension corner and nontrivial edge modes occur at tailored positions within the system bulk states instead of the explicit system boundaries. Our findings uncover the mechanism of non-localized hierarchical non-trivial topological states and offer distinct paradigms for diffusive transport field management. [ABSTRACT FROM AUTHOR]

Herein, lead‐free, mixed‐halide perovskites of cesium bismuth bromide/iodide are synthesized by a hydrothermal method, and their structures and optical properties of the solid solution compounds are examined. The synthesized compounds exhibit X‐ray diffraction patterns similar to that of trigonal Cs3Bi2Br9 (CBB), whose reflections are shifted to lower angles depending on the experimental iodine content. Very interestingly, even with the excessive introduction of iodine content in nominal, the symmetry of the crystals is kept to be trigonal, indicating that bromide CBB and iodide Cs3Bi2I9 (CBI) are crystallographically mixed in a facile way, although the stable crystal form of CBI is hexagonal. The optical properties of bandgap energy Eg and photoluminescence (PL) for the synthesized crystals are also examined. It is found that Eg decreases and PL peak position is correspondingly shifted to a longer wavelength with an increase in the experimental iodine content due to their band‐to‐band transitions. Moreover, first‐principles calculation suggests the reduction of Eg with iodine content and the varied nature of band structure from direct (trigonal CBB) to indirect (trigonal CBI) transition. These novel findings can make the proposed strategy successful for developing lead‐free, mixed‐halide Bi‐based perovskite crystals with the tunability of their optical properties. [ABSTRACT FROM AUTHOR]

Thin layers of ferromagnetic/non-magnetic bimetallic heterostructures have become the focal point of spintronics, primarily due to their capacity to convert spin to charge current, leveraging the spin- and inverse spin Hall effects. However, the interfacial properties and morphologies can significantly influence this conversion. Hence, we employed molecular dynamics calculations to model the construction of the Fe/Pt interface at various bilayer growth temperatures and Pt deposition rates. We then experimentally evaluated the modeling using x-ray methods to resolve the chemical and structural state of the interface. The calculations revealed moderate diffusive phenomena between the adjacent layers and an interfacial roughness of less than 1 nm, consistent with the experimental observations. In cases where plastic relaxation of the Fe/Pt interface is insufficient, lattice deformation is mitigated by a local pseudomorphic growth caused by transformation of the Pt crystal symmetry. Additionally, interfacial planar defects may emerge as a complementary stress-relieving mechanism to misfit dislocations. By combining the experimental and computational findings, we propose optimized growth conditions for an "ideal" Fe/Pt interface, which could serve as a useful tool to control the efficiency of spin-to-charge conversion. [ABSTRACT FROM AUTHOR]

Using muon spin relaxation measurements on formamidinium lead iodide [ FAPbI 3 , where FA denotes HC( NH 2) 2 ], we show that, among the five structurally distinct phases of FAPbI 3 exhibited through two different temperature hysteresis, the reorientation motion of FA molecules is quasi-static below ≈ 50 K over the time scale of 10 − 6 s in the low-temperature (LT) hexagonal (Hex-LT, <160 K) phase, which has a relatively longer photo-excited charge carrier lifetime (τ c ∼ 10 − 6 s). In contrast, a sharp increase in the FA molecular motion was found above ≈ 50 K in the Hex-LT phase, LT-tetragonal phase (Tet-LT, <140 K), the high-temperature (HT) hexagonal phase (Hex-HT, 160–380 K), and the HT-tetragonal phase (Tet-HT, 140–280 K), where τ c decreases with increasing temperature. More interestingly, the reorientation motion is further promoted in the cubic phase at higher temperatures (>380/280 K), while τ c is recovered to comparable or larger than that of the LT phases. These results indicate that there are two factors that determine τ c , one related to the local reorientation of cationic molecules that is not unencumbered by phonons and the other to the high symmetry of the bulk crystal structure. [ABSTRACT FROM AUTHOR]

Using muon spin relaxation measurements on formamidinium lead iodide [ FAPbI 3 , where FA denotes HC( NH 2) 2 ], we show that, among the five structurally distinct phases of FAPbI 3 exhibited through two different temperature hysteresis, the reorientation motion of FA molecules is quasi-static below ≈ 50 K over the time scale of 10 − 6 s in the low-temperature (LT) hexagonal (Hex-LT, <160 K) phase, which has a relatively longer photo-excited charge carrier lifetime (τ c ∼ 10 − 6 s). In contrast, a sharp increase in the FA molecular motion was found above ≈ 50 K in the Hex-LT phase, LT-tetragonal phase (Tet-LT, <140 K), the high-temperature (HT) hexagonal phase (Hex-HT, 160–380 K), and the HT-tetragonal phase (Tet-HT, 140–280 K), where τ c decreases with increasing temperature. More interestingly, the reorientation motion is further promoted in the cubic phase at higher temperatures (>380/280 K), while τ c is recovered to comparable or larger than that of the LT phases. These results indicate that there are two factors that determine τ c , one related to the local reorientation of cationic molecules that is not unencumbered by phonons and the other to the high symmetry of the bulk crystal structure. [ABSTRACT FROM AUTHOR]

We study the evolution of band topology under external pressure in rare-earth gadolinium mono-antimonide (GdSb) using first-principles calculations. This material crystallizes in a rocksalt-type structure and shows a structural phase transition (SPT) to a CsCl-type structure at 26.1 GPa. The phonon dispersions are analyzed to ascertain the dynamical stability of this material. We use hybrid density functional theory with the inclusion of spin–orbit coupling to investigate the structural, electronic, and topological phase transitions (TPTs). At ambient pressure, GdSb shows a topologically trivial state which is in agreement with existing experimental reports. The first TPT is observed at 6 GPa of hydrostatic pressure (at the high symmetry X -point) which is verified with the help of single-band inversion and surface state analysis along the (001) plane. The non-zero value of the first Z2 topological invariant and the presence of the Dirac cone also confirm the topological phase of this material. A further increase in pressure to 12 GPa results in two band inversions at Γ - as well as X - points, which corresponds to the trivial nature of GdSb. The same is also verified with (0; 000) values of Z2 topological invariants and a pair of Dirac cones in surface states. It is noted that the crystal symmetries are preserved throughout the study and the TPT values are much lower than the SPT pressure, i.e. 26.1 GPa. [ABSTRACT FROM AUTHOR]

Organic-cation engineering has recently proven effective in flexibly regulating two-dimensional hybrid organic–inorganic perovskites (2D HOIPs) to achieve a diversity of newly emerging applications. There have been many mechanistic studies based on the structural tunability of organic cations; nevertheless, those with an emphasis on the effect solely caused by the organic cations remain lacking. To this end, here we deliberately design a set of 2D HOIPs in which the inorganic layers are kept nearly intact upon cation modification, i.e., the precursor phenethylammonium lead iodide and its four derivatives with the phenyl group's para-position H being replaced by CH3, F, Cl, and Br. By means of femtosecond time-resolved transient absorption spectroscopy and temperature-dependent/time-resolved photoluminescence spectroscopy, we interrogate the subtle impact of cation modification on phonon dynamics, coherent phonon modes, phonon-dressed exciton dynamics, and excitonic emissions. A concerted trend for phonon lifetimes and exciton relaxation lifetimes regulated by cation modification is revealed, evidencing the existence of strong exciton–phonon coupling in this 2D HOIP system. The observed mass effect can be ascribed to the change in moment of inertia of organic cations. In addition, we observe an interesting interplay of exciton kinetics pertinent to population transfers between two emissive states, likely linked to the subtle variation in crystal symmetry induced by cation modification. The mechanistic insights gained from this work would be of value for the 2D HOIPs-based applications. [ABSTRACT FROM AUTHOR]

Coherent nonlinear optical μ -spectroscopy is a frequently used tool in modern material science as it is sensitive to many different local observables, which comprise, among others, crystal symmetry and vibrational properties. The richness in information, however, may come with challenges in data interpretation, as one has to disentangle the many different effects like multiple reflections, phase jumps at interfaces, or the influence of the Guoy-phase. In order to facilitate interpretation, the work presented here proposes an easy-to-use semi-analytical modeling Ansatz, which bases upon known analytical solutions using Gaussian beams. Specifically, we apply this Ansatz to compute nonlinear optical responses of (thin film) optical materials. We try to conserve the meaning of intuitive parameters like the Gouy-phase and the nonlinear coherent interaction length. In particular, the concept of coherence length is extended, which is a must when using focal beams. The model is subsequently applied to exemplary cases of second- and third-harmonic generation. We observe a very good agreement with experimental data, and furthermore, despite the constraints and limits of the analytical Ansatz, our model performs similarly well as when using more rigorous simulations. However, it outperforms the latter in terms of computational power, requiring more than three orders less computational time and less performant computer systems. [ABSTRACT FROM AUTHOR]

The free-field switching of the perpendicular magnetization by the out-of-plane polarized spin current induced spin-orbit torque makes it a promising technology for developing high-density memory and logic devices. The materials intrinsically with low symmetry are generally utilized to generate the spin current with out-of-plane spin polarization. However, the generation of the out-of-plane polarized spin current by engineering the symmetry of materials has not yet been reported. Here, we demonstrate that paramagnetic CaRuO3 films are able to generate out-of-plane polarized spin current by engineering the crystal symmetry. The non-uniform oxygen octahedral tilt/rotation along film's normal direction induced by oxygen octahedral coupling near interface breaks the screw-axis and glide-plane symmetries, which gives rise to a significant out-of-plane polarized spin current. This spin current can drive field-free spin-orbit torque switching of perpendicular magnetization with high efficiency. Our results offer a promising strategy based on crystal symmetry design to manipulate spin current and could have potential applications in advanced spintronic devices. The authors realize generation of out-of-plane polarized spin current in perovskite oxide CaRuO3 with reduced crystal symmetry by engineering the oxygen octahedra, which can drive efficient field-free switching of perpendicular magnetization. [ABSTRACT FROM AUTHOR]

General derivation of the well-known Ren–Otsuka relationship, 1 α d T o d x = − α β (where T o , x, α and β (> 0) are the transformation temperature and composition, as well as the composition and temperature coefficient of the critical shear constant, c′, respectively) for shape memory alloys, SMAs, is provided based on the similarity of interatomic potentials in the framework of dimensional analysis. A new dimensionless variable, t o x = T o x T m x , describing the phonon softening (where Tm is the melting point) is introduced. The dimensionless values of the heat of transformation, ΔH, and entropy, ΔS, as well as the elastic constants c′, c44, and A = c 44 c ′ are universal functions of to(x) and have the same constant values at to(0) within sub-classes of host SMAs having the same type of crystal symmetry change during martensitic transformation. The ratio of d t o d x and α has the same constant value for all members of a given sub-class, and relative increase in c′ with increasing composition should be compensated by the same decrease in to. In the generalized Ren–Otsuka relationship, the anisotropy factor A appears instead of c′, and α as well as β are the differences between the corresponding coefficients for the c44 and c′ elastic constants. The obtained linear relationship between h and to rationalizes the observed empirical linear relationships between the heat of transformation measured by differential scanning calorimetry (DSC) (QA⟶M) and the martensite start temperature, Ms. [ABSTRACT FROM AUTHOR]

[Display omitted] The conventional Hall effect is linearly proportional to the field component or magnetization component perpendicular to a film. Despite the increasing theoretical proposals on the Hall effect to the in-plane field or magnetization in various special systems induced by the Berry curvature, such an unconventional Hall effect has only been experimentally reported in Weyl semimetals and in a heterodimensional superlattice. Here, we report an unambiguous experimental observation of the antisymmetric planar Hall effect (APHE) with respect to the in-plane magnetic field in centrosymmetric rutile RuO 2 and IrO 2 single-crystal films. The measured Hall resistivity is found to be linearly proportional to the component of the applied in-plane magnetic field along a particular crystal axis and to be independent of the current direction or temperature. Both the experimental observations and theoretical calculations confirm that the APHE in rutile oxide films is induced by the Lorentz force. Our findings can be generalized to ferromagnetic materials for the discovery of anomalous Hall effects and quantum anomalous Hall effects induced by in-plane magnetization. In addition to significantly expanding knowledge of the Hall effect, this work opens the door to explore new members in the Hall effect family. [ABSTRACT FROM AUTHOR]

Piezoelectric materials with tunable photoluminescence have gained widespread attention for their application in optical communications and optoelectronic sensing devices. This has provided new opportunities to explore the possibility of developing flexible piezoelectric devices with both piezoelectricity and photoluminescence for multifunctional applications. In this study, we prepared a crystalline Pr‐doped perovskite BaTiO3 (BPTO) film on a flexible mica substrate using the radio‐frequency (RF) sputtering technique. The photoluminescence intensity remarkably increased by about 210% when external mechanical stress was applied to the film. This remarkable increase in photoluminescence is attributed to lattice distortion and a decrease in crystal symmetry. The BPTO film also exhibited reversible and high‐endurance behavior even after 103 fatigue bending cycles. Moreover, the BPTO film was utilized as a piezoelectric nanogenerator device, which demonstrated a maximum output voltage of about 2.68 V when external stress was applied through palm tapping. The nanogenerator device yielded an instantaneous output power of 1.80 μW with an external load resistance of 0.8 MΩ. These versatile and robust properties of the BPTO film demonstrate its potential for future development of lead‐free self‐powered optoelectronic sensing applications, such as artificial intelligence and biomedical devices. [ABSTRACT FROM AUTHOR]

Crystals of a new high-symmetry structural modification of Cs2HIn(IO3)6 which crystallizes in sp. gr. R with the unit cell parameters a = 11.8999(4) Å, c = 11.6513(5) Å, was obtained under hydrothermal conditions. The crystal-chemical comparison with the previously characterized triclinic modification of this compound was carried out. Both structures are composed of isolated [In(IO3)6]3– blocks. The new modification belongs to the family of trigonal iodates isostructural with the compound K2Ge(IO3)6. The local symmetry of individual [M(IO3)6] blocks (M = Ge, Ti, Sn, Ga, In, and some other metals) was analyzed. The structural systematics of iodate families was proposed based on the comparative crystal-chemical analysis. The influence of the cation composition and the synthesis conditions on the symmetry and topology of the crystal structures and the effect of the local symmetry of individual blocks on the physical properties of the compounds are discussed. [ABSTRACT FROM AUTHOR]

Predicting crystal symmetry simply from chemical composition has remained challenging. Several machine‐learning approaches can be employed, but the predictive value of popular crystallographic databases is relatively modest due to the paucity of data and uneven distribution across the 230 space groups. In this work, virtually all crystallographic information available to science has been compiled and used to train and test multiple machine‐learning models. Composition‐driven random‐forest classification relying on a large set of descriptors showed the best performance. The predictive models for crystal system, Bravais lattice, point group and space group of inorganic compounds are made publicly available as easy‐to‐use software downloadable from https://gitlab.com/vishsoft/cosy. [ABSTRACT FROM AUTHOR]

Rotation axes (together with rotation angles) are often used to describe crystal orientations and misorientations, and they are also needed to characterize some properties of crystalline materials. Since experimental orientation data are subject to errors, the directions of the axes obtained from such data are also inaccurate. A natural question arises: given the resolution of input rotations, what is the average error of the rotation axes? Assuming that rotation data characterized by a rotation angle ω deviate from the actual data by error rotations with fixed angle δ but which are otherwise random, the average error of the rotation axes of the data is expressed analytically as a function of ω and δ. A scheme for using this formula in practical cases when rotation errors δ follow the von Mises–Fisher distribution is also described. Finally, the impact of crystal symmetry on the determination of the average errors of the axis directions is discussed. The presented results are important for assessing the reliability of rotation axes in studies where the directions of crystal rotations play a role, e.g. in identifying deformation slip mechanisms. [ABSTRACT FROM AUTHOR]

We analyze the transverse electro-optic (EO) effect in an arbitrary direction in LiNbO3 (LN) and LiTaO3 (LT) crystals based on the Fresnel index ellipsoid theory. A set of analytical formulas for calculating the birefringence in any direction in a crystal of the lowest symmetry is first deduced. The maximum magnitudes of the transverse EO effect appear along the directions that are turned out from the optic axis on the angles θm (φ = 30°, 150° or 270°) or 180°− θm (φ = 90°, 210° or 330°), the angles θm of congruent LN and LT crystals are 36° and 59.5°, respectively. For experimental verification, the (yzw)θm cut congruent LN and LT crystals were prepared. The half-wave voltage (HWV) of the (yzw)36° cut LN crystals is half that of the x-cut LN crystals and is only 30% that of the z-cut LN crystals, and the HWV of the (yzw)59.5° cut LT crystals is 7% higher than that of the x-cut LT crystals, the experimental results agree well with the theoretical analysis. The crystals with the optimized cell geometries are more practical because of the low HWV and lower sensitivity of birefringence to temperature. [ABSTRACT FROM AUTHOR]

Compared with powder particles, ceramic block piezocatalyst possesses the advantages of high cycle stability, decreasing secondary pollution, and easy recovery. Herein, with a simple strategy of the poling procedure, the piezocatalytic activity of 0.96K0.5Na0.5NbO3‐0.04Bi0.5Na0.5ZrO3 (abbreviated as 0.96KNN‐0.04BNZ) ceramic blocks can be considerably improved. A reaction rate constant k value of 14.70×10−3 min−1 in the poled sample can be obtained to degrade Rhodamine B, which is 3.44 times that of the unpoled one. Meanwhile, the poled sample also has good degradation effects against methylene blue and amino black 10B. The improvement of piezocatalytic activities originates from the reduction of crystal symmetry and the enhancement of electron‐hole pair separation, which accelerates the generation of charge carriers. This research displays a unique lead‐free bulk piezocatalyst and a convenient method for enhancing its piezocatalytic activity. [ABSTRACT FROM AUTHOR]

The Azotobacter vinelandii FeSII protein forms an oxygen‐resistant complex with the nitrogenase MoFe and Fe proteins. FeSII is an adrenodoxin‐type ferredoxin that forms a dimer in solution. Previously, the crystal structure was solved [Schlesier et al. (2016), J. Am. Chem. Soc.138, 239–247] with five copies in the asymmetric unit. One copy is a normal adrenodoxin domain that forms a dimer with its crystallographic symmetry mate. The other four copies are in an 'open' conformation with a loop flipped out exposing the 2Fe–2S cluster. The open and closed conformations were interpreted as oxidized and reduced, respectively, and the large conformational change in the open configuration allowed binding to nitrogenase. Here, the structure of FeSII was independently solved in the same crystal form. The positioning of the atoms in the unit cell is similar to the earlier report. However, the interpretation of the structure is different. The 'open' conformation is interpreted as the product of a crystallization‐induced domain swap. The 2Fe–2S cluster is not exposed to solvent, but in the crystal its interacting helix is replaced by the same helix residues from a crystal symmetry mate. The domain swap is complicated, as it is unusual in being in the middle of the protein rather than at a terminus, and it creates arrangements of molecules that can be interpreted in multiple ways. It is also cautioned that crystal structures should be interpreted in terms of the contents of the entire crystal rather than of one asymmetric unit. [ABSTRACT FROM AUTHOR]

Transparent spinel with high real in-line transmittance (RIT up to 79%) was prepared from commercial spinel powder by capsule-free hot isostatic pressing (HIP). Optimal pre-sintering conditions were found in order to enhance the RIT values and doping with Cr3+ (0.01–0.04 at%) and Tb3+ (0.05–0.125 at%) secured photoluminescence. The incorporation of the dopants in tested range does not noticeably reduced the RIT. The Cr3+-doped MgAl 2 O 4 shows efficient narrow red emission at about 685 nm (R-line) due to the 2E g →4A 2g transition of Cr3+ ions located in octahedral sites of D 3d local symmetry with a strong crystal field. The Tb3+-doped MgAl 2 O 4 ceramics have shown emissions from blue to red spectral range (5D 4 →7F 3–6 transitions), with prominent green emission centered at 545 nm. The maximal emission intensity was achieved at 0.075 at% of Tb3+, Further increase of Tb3+ content led to the concentration quenching caused by Tb3+ ions segregation at the grain boundaries. [ABSTRACT FROM AUTHOR]

Here, the mechanism of charge‐disproportionation (CD) in BaBiO3 (BBO) using density functional theory under different crystal symmetries and by employing strain as an external perturbation is investigated. The competition between Bi 6sp–O 2p (s‐p) and O 2p–O 2p (p‐p) or Bi 6p–O 2p charge fluctuations decides the electronic ground state, CD, and bond‐disproportionation (BD) in BBO. An extended Hubbard Hamiltonian involving onsite (U) and long‐range (V) coulomb repulsion is also employed to ascertain the microscopic conditions for forming the lone pair on the bismuth site. A strong tensile strain increases p‐p fluctuation and drives the system into a strong negative‐CT character, while a strong compressive strain favors s‐p fluctuation leading to the enhanced positive‐CT character. This indicates that the change transfer energy of the bulk BBO can be tuned with external strain. [ABSTRACT FROM AUTHOR]

We demonstrate that AlGaAs thin films and metasurfaces generate a distinct intrinsic nonlinear geometric phase in their second harmonic signals, differing significantly from previous studies on nonlinear dielectric, plasmonic, or hybrid metasurfaces. Unlike conventional observations, our study reveals that the second harmonic phase remains unaffected by the linear optical response at both pump and harmonic wavelengths, introducing a novel realm of achievable phase functions yet to be explored. Furthermore, we explore the interplay between this intrinsic nonlinear geometric phase and the geometric phase induced by rotations of nanoresonators within metasurface arrangements. Our findings extend the capabilities of nonlinear wavefront shaping metasurfaces, exploiting phase manipulation to uncover unique phenomena exclusive to the nonlinear regime. [ABSTRACT FROM AUTHOR]

Here, the mechanism of charge‐disproportionation (CD) in BaBiO3 (BBO) using density functional theory under different crystal symmetries and by employing strain as an external perturbation is investigated. The competition between Bi 6sp–O 2p (s‐p) and O 2p–O 2p (p‐p) or Bi 6p–O 2p charge fluctuations decides the electronic ground state, CD, and bond‐disproportionation (BD) in BBO. An extended Hubbard Hamiltonian involving onsite (U) and long‐range (V) coulomb repulsion is also employed to ascertain the microscopic conditions for forming the lone pair on the bismuth site. A strong tensile strain increases p‐p fluctuation and drives the system into a strong negative‐CT character, while a strong compressive strain favors s‐p fluctuation leading to the enhanced positive‐CT character. This indicates that the change transfer energy of the bulk BBO can be tuned with external strain. [ABSTRACT FROM AUTHOR]

Crystals of a new high-symmetry structural modification of Cs2HIn(IO3)6 which crystallizes in sp. gr. R with the unit cell parameters a = 11.8999(4) Å, c = 11.6513(5) Å, was obtained under hydrothermal conditions. The crystal-chemical comparison with the previously characterized triclinic modification of this compound was carried out. Both structures are composed of isolated [In(IO3)6]3– blocks. The new modification belongs to the family of trigonal iodates isostructural with the compound K2Ge(IO3)6. The local symmetry of individual [M(IO3)6] blocks (M = Ge, Ti, Sn, Ga, In, and some other metals) was analyzed. The structural systematics of iodate families was proposed based on the comparative crystal-chemical analysis. The influence of the cation composition and the synthesis conditions on the symmetry and topology of the crystal structures and the effect of the local symmetry of individual blocks on the physical properties of the compounds are discussed. [ABSTRACT FROM AUTHOR]

Improving ferro-piezoelectric properties of niobate-based perovskites is highly desirable for developing eco-friendly high-performance sensors and actuators. Although electro-strain coupling is usually obtained by constructing multiphase boundaries via complex chemical compositions, defect engineering can also create opportunities for novel property and functionality advancements. In this work, a representative tetragonal niobate-based perovskite, i.e., KNbO3, is studied by using first-principles calculations. Two intrinsic types of Nb antisite defect complexes are selected to mimic alkali-deficiency induced excess Nb antisites in experiments. The formation energy, electronic profiles, polarization, and piezoelectric constants are systematically analyzed. It is shown that the structural distortion and chemical heterogeneity around the energetically favorable antisite pair defects, i.e., ( Nb K 4 · + K Nb 4 ′ ), lower the crystal symmetry of KNbO3 from tetragonal to triclinic phase, and facilitate polarization emergence and reorientation to substantially enhance intrinsic ferro-piezoelectricity (i.e., spontaneous polarization Ps of 68.2 μC/cm2 and piezoelectric strain constant d33 of 228.3 pC/N) without complicated doping and alloying. [ABSTRACT FROM AUTHOR]

Details on anisotropic magnon dispersion in van der Waals (vdW) ferromagnetic insulators CrPS4 and CrSBr are reported, driven by anisotropic Heisenberg exchange couplings arising from in‐plane broken crystal symmetry. The anisotropic magnon dispersion contributes to longitudinal and transverse magnon currents generating the anisotropic spin Seebeck effect (ASSE) and the thermal Hall effect (THE) accompanied with spin Nernst effect (SNE), requiring neither external magnetic field nor Berry curvature. In CrPS4, the ASSE exhibits a very large anisotropy ratio of over 100% as the thermal gradient along different main axes, and this ratio can be further tuned by temperature or a gate current. The THE and SNE unconstrained by spin‐orbit coupling (SOC) emerge when the thermal gradient is not parallel to the main axis, characterized by a large Hall angle ≈ 0.4. Compared to CrPS4, CrSBr exhibits a more limited anisotropic magnon transport owing to the less variation in magnon group velocities along different main axes. Moreover, the reversed magnitude relationship of magnon group velocities leads to the transverse magnon current being oriented in the opposite direction. These findings identify low‐symmetry vdW magnetic materials as a promising framework for generation and manipulation of anisotropic magnon transport, relevant for spincaloritronic devices in the ultrathin regime. [ABSTRACT FROM AUTHOR]

The generally undesirable bandgap and electron–hole complexation of inorganic sonosensitizers limit the efficiency of reactive oxygen species (ROS) generation, affecting the effectiveness of sonodynamic therapy (SDT). Comparatively, the novel polyvinylpyrrolidone‐modified copper bismuthate (PCBO) sonosensitizers are manufactured for a "three‐step" SDT promotion. In brief, first, the strong hybridization between Bi 6s and O 2p orbitals in PCBO narrows the bandgap (1.83 eV), facilitating the rapid transfer of charge carriers. Additionally, nonequivalent [CuO4]6− layers reduce crystal symmetry, confer PCBO unique piezoelectricity, and improve electron–hole separation under ultrasonic (US) excitation. This allows PCBO to convert US energy into chemical energy to produce ROS, achieving the accumulation of abundant ROS, resulting in apoptosis and tumor suppression. Concurrently, PCBO also acts as a glutathione scavenger to reduce tumor antioxidant capacity and improve efficacy. To the best of authors understanding, this study reveals PCBO as an innovative piezoelectric sonosensitizer and provides a meaningful paradigm for designing energy conversion strategies for tumor suppression. [ABSTRACT FROM AUTHOR]

A metaheuristic algorithm named the Crystal Structure Algorithm (CrSA), which is inspired by the symmetric arrangement of atoms, molecules, or ions in crystalline minerals, has been used for the accurate modeling of Mono Passivated Emitter and Rear Cell (PERC) WSMD-545 and CS7L-590 MS solar photovoltaic (PV) modules. The suggested algorithm is a concise and parameter-free approach that does not need the identification of any intrinsic parameter during the optimization stage. It is based on crystal structure generation by combining the basis and lattice point. The proposed algorithm is adopted to minimize the sum of the squares of the errors at the maximum power point, as well as the short circuit and open circuit points. Several runs are carried out to examine the V-I characteristics of the PV panels under consideration and the nature of the derived parameters. The parameters generated by the proposed technique offer the lowest error over several executions, indicating that it should be implemented in the present scenario. To validate the performance of the proposed approach, convergence curves of Mono PERC WSMD-545 and CS7L-590 MS PV modules obtained using the CrSA are compared with the convergence curves obtained using the recent optimization algorithms (OAs) in the literature. It has been observed that the proposed approach exhibited the fastest rate of convergence on each of the PV panels. [ABSTRACT FROM AUTHOR]