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Silver nanowires (AgNW) mixed with nanocellulose nanowires (NCNW) are deposited in photolithgraphed gratings of varying depth. The nanocellulose onto which the AgNWs are mixed is of varying length. It is found that the recirculation flow is larger when the length of the NCNW is longer, and the grating used is deeper. The electrical properties of the resulting quasi‐1D electrode is tested both before it is transferred into the nanocellulose paper and after, and it is observed that it retains the same order of magnitude for the conductivities as the 0.3 and 0.2%wt concentrations for the bare AgNW. This is attributed to the use of the NCNW, at high concentrations. Using the NCNW in the mixtures allows for the AgNW to be transferred from the gratings to any substrate. Using the NC paper allows to obtain a nearly transparent or translucent nearly 1D electrode, where 1D refers to the fact the length of the obtained electrode far exceeds its width. [ABSTRACT FROM AUTHOR]

This is the fifteenth volume of I Physica Status Solidi B i focussed on materials and models showing negative Poisson's ratio (PR), which are often called auxetics, and other systems of unusual, e.g., "negative", characteristics. SP [ sp [1] SP ] sp This time it contains 19 papers which are grouped into three sections. This non-classical effect cannot occur in classical thermo-elasticity but is allowable in Cosserat solids. SP [ sp [17] SP ] sp Next, I Elena Pasternak and Arcady Dyskin i propose a mechanism to control the constriction of elastic rod modulus by lateral compression. This, amongst other things, opens a way to design materials ensuring vibration isolation. SP [ sp [18] SP ] sp I Haifeng Ruan and Dong Li i propose a hierarchical acoustic metamaterial with a spider-web-like structure. [Extracted from the article]

In order to achieve the attenuation of low‐frequency sound, in this paper, a hybrid metamaterial structure with a complete band gap below 500 Hz is proposed, which is subjected to second‐order fractal, series fusion, and whether the structure is framed or not to form 8 different structures. Based on the finite element method and Bloch's theorem, the bandgap and transport properties of all model structures are evaluated, and the bandgap and propagation properties of metamaterial structures with different fractal levels are elucidated in terms of band structure and group velocity. In addition, the third‐order fractal structure and the dependence of the band gap on the material are also studied. The results show that the structure has a superior band gap width, and the complete band gap of its tandem fusion structure accounts for up to 45.502% in the range of 500 Hz, and the second‐order fractal has a complete band gap of 45.588% in the range of 1000 Hz. Compared with other structures, it can produce lower and better band gap. The research in this paper provides a new strategy for realizing acoustic metamaterial structures with low frequency band gaps. [ABSTRACT FROM AUTHOR]

To improve the electron collection efficiency of gallium nitride (GaN) nanorod array photocathode, external electric field is used to assist collect photoelectrons and a theoretical model of field‐assisted photoelectric emission for GaN nanorod array is established herein. The results indicate that inclined incident light can improve the photoelectron collection efficiency on the side surface of the nanorod and that external electric field can promote the drifting of the photoelectron to the top surface of the nanorod. The square array with a filling fraction of 0.7 reaches its maximum photoelectron collection efficiency at the incident angle of 5° and field intensity of 0.1 V μm−1. This paper might play a theoretical guiding role in the fabrication of photodetectors with high photoelectric conversion efficiency. [ABSTRACT FROM AUTHOR]

In this paper, the authors consider the processes that occur at the interfaces during nanowires (NWs) growth by the vapor→droplet liquid→solid mechanism (VLS), and how that leads to the faceting of the sidewall surface of the NWs. It is shown that faceting is possible only when the wetting scenario of the VLS growth of the NWs is accomplished due to the exit of the oblique closed‐packed faces to the sidewall surface of the NWs. Those oblique closed‐packed faces emerge at the crystallization front near the triple phase line. The faceting of the sidewall surface of the NWs can be controlled (i) by changing the contact angle of the catalyst droplet on the top of the NWs with the appropriate catalysts; (ii) by introducing the impurities into the gas phase, which decreases the free surface energy of the catalyst droplet; or (iii) by changing the temperature. [ABSTRACT FROM AUTHOR]

To facilitate the calculation of the fourth‐order crystal‐field (CF) splitting moment, which in a complex way depends on the split state |J⟩, a time saving formula is elaborated, which is positively verified for several cubic systems RE3+: Cs2NaLaCl6. The appropriate crystal‐field parameters (CFPs) have to be substituted to the presented formula. However, the question is which ones. The clear answer proven in the paper is that single‐state CFPs should necessarily be used. To test the approach, a few cubic systems, for which such single‐state CFPs are available, have been studied. Conventionally fitted CFPs, averaged over the entire electron configuration, do not satisfy the equation, which contradicts the fundamental principle of the CF theory. Such verification significantly limits the physical meaning and applicability of the conventional HCF fitted parameterizations. [ABSTRACT FROM AUTHOR]

A more accurate synaptic modeling based on oxygen vacancy conductive mechanism is presented in this paper. Two internal state variables, that is, the length and area of conductive region, are used to describe the vertical and lateral growth/dissolution dynamics of the region, based on the physical mechanisms of ion drift and two different diffusion effects. Since the effect of length on the electric field is not negligible, it is introduced into the modeling. In addition, the Fick and Soret diffusions are considered, because they cause the model to produce a "forgetting" property and a "memory" retention. By the comparisons, this modeling captures the actual device better than others. In addition, the previous models can be derived from this one. Some rough analysis suggests that the modeling possibly captures different memristors by adjusting the parameters, and the effects of oxygen concentration and temperature on synapse can also be considered. Therefore, this modeling is more comprehensive and generalized. Several important synaptic functions are simulated, including excitatory postsynaptic current, paired‐pulse facilitation, spike‐rate‐dependent plasticity, and spike‐timing‐dependent plasticity, which may provide a theoretical basis for some potential applications such as artificial neural networks and artificial intelligence. [ABSTRACT FROM AUTHOR]

Electrochemical water‐splitting, sustained by renewable energy, is aimed at green H2 production. Efficient and sustainable electrocatalysts are required for a proper energy transition. Oxygen evolution reaction (OER) in alkaline electrolyte can be pursued by using earth‐abundant elements‐based catalysts, such as Ni oxyhydroxides. A proper optimization of intrinsic properties and synthesis procedure is still needed. Herein, the synthesis of Ni/NiO nanoparticles (NPs) through a physical and green technique, pulsed laser ablation in liquid (PLAL), is presented. Ablating a Ni target in deionized water, at different ablation times, leads to NP dispersions used for realization of OER electrode onto graphene paper. Ion‐beam analysis of catalysts amount and homogeneity of NP‐based electrode is performed for the electrode optimization in terms of electrochemical performances. An overpotential at 10 mA cm−2 of 306 mV is achieved for 40 μg cm−2 of catalyst, while lowering the catalyst amount to 8 μg cm−2, unprecedented turnover frequency of 0.20 s−1 and mass activity of ≈1.3 A mg−1 are reached. These data show that Ni/NiO NPs produced by PLAL are highly effective for OER in alkaline media and encourage the use of PLAL as a green and efficient technique for electrocatalyst production. [ABSTRACT FROM AUTHOR]

The ICPS series traditionally encompasses a variety of topics spanning device physics, quantum technologies, spin physics, wide bandgap materials, light-matter interactions, and other branches of materials science, physics and engineering. It is my pleasure to write this preface to the Special Section in the May 2023 issue of I pss(b) i , dedicated to the collection of selected works presented during the 35 SP th sp International Conference on Physics of Semiconductors (ICPS) held in Sydney, Australia in 2022. As we are preparing for the next meeting in Ottawa, Canada, the collection of papers should inspire our junior colleagues, that not only semiconductor physics is here to stay, but in fact, it is a multi-disciplinary and burgeoning field of research. [Extracted from the article]

Obtaining a reliable positive‐type (p‐type) GaN semiconductor is difficult because of the unipolarity of GaN. This difficulty is one of the bottlenecks restricting the development of GaN‐based optoelectronic devices. To address this problem, this paper adopted the method of generalized gradient approximation (GGA) plane wave ultrasoft pseudopotential based on the framework of density functional theory to construct Ga35MN36, Ga34MN36, and Ga34MHiN36 (M = Be/Mg/Ca; Hi = interstitial hydrogen) models. Ga35MN35 and Ga35MHiN35 (M = Be/Mg/Ca) models were also constructed. Results of our calculations indicated that the Ga35MN35 and Ga35MHiN35 (M = Be/Mg/Ca) models cannot achieve a p‐type doping system. Furthermore, the formation energy of Ga34MN36 and Ga34MHiN36 (M = Be/Mg/Ca) systems was greater under Ga‐rich conditions than that under N‐rich conditions, indicating that both doping systems more readily formed and had a more stable structure under N‐rich conditions. Moreover, the formation energy of Ga34MHiN36 (M = Be/Mg/Ca) system was lower than that of Ga34MN36 (M = Be/Mg/Ca) system, and the existence of interstitial H proved to be beneficial to the improvement in system stability. The Ga34CaHiN36 system had the largest hole mobility and the best conductivity. Therefore, the Ga34CaHiN36 system is an ideal material for the application of conductive GaN devices. This study provides guidance into the preparation of p‐type conductive GaN materials. [ABSTRACT FROM AUTHOR]

Status Solidi B i B 2020 b , I 257 i , 1000755 DOI: 10.1002/pssb.201900755 Recent measurements revealed a minor error in Figure 3c of the published paper by V. V. Vogler-Neuling et al., I Phys. In the running text on page 5: "The long axis of the dipole is parallel to the orientation of the rods (cf. Solution-Processed Barium Titanate Nonlinear Woodpile Photonic Structures with Large Surface Areas. [Extracted from the article]

This special issue "Interdisciplinary Research in Materials Science" contains a culmination of FRIMS research activities to date as well as a selection of the papers presented at the above symposium. The Frontier Research Institute for Materials Science (FRIMS) was established in 2016 as a Center of Excellence at Nagoya Institute of Technology (NITech). In this symposium that 116 scientists and students attended, FRIMS members presented their research results as the culmination of the last six years of research at FRIMS. [Extracted from the article]

Herein, a ternary system of TeO2–ZnO–Na2O (TZN) with competitive roles of covalent Zn–O and ionic Na–O bonds in tellurite glassy network is examined for high‐temperature in situ X‐ray diffraction (XRD) and Raman spectroscopy. TZN glasses are doped with Nd2O3 and the effects of Nd doping on the crystallization of glasses are also written. In situ high‐temperature XRD permits the assignment of each of the differential scanning calorimetry (DSC) crystallization peaks (the first crystallization peak (Tc1) is related to sodium‐based crystalline phases, while the second crystallization peak (Tc2) is correlated with tellurium‐/zinc‐based crystalline phases). The study of in situ high‐temperature Raman spectroscopy shows that Tc1 shows γ‐TeO2 crystallized phase‐like peaks while Tc2 crystallization has more α‐TeO2‐crystallized phase‐like peaks. Comparison at the same temperature (430 °C) permits a first understanding of the structural changes of the glasses in terms of the evolution first to α‐TeO2, ZnO, ZnTeO3, and Zn2Te3O8 crystalline phases compared with Na10Zn4O9 phase. The ZnTeO3 and Zn2Te3O8 crystallization evolution is also compared between the Nd‐doped and nondoped glasses, which gives more insight into the tellurite glass structures. [ABSTRACT FROM AUTHOR]

Similar to the cancelled Compound Semiconductor Week 2020 (CSW'2020), CSW'2021 was supposed to be an onsite conference in Stockholm but had to be rescheduled as a virtual event because of the prevailing worldwide pandemic situation. CSW thereby takes the role of providing all aspects of compound semiconductors and their applications in electronics, photonics and emerging fields. CSW'2021 was organized as a joint venue for the 47th International Symposium on Compound Semiconductors (ISCS) and the 32nd International Conference on Indium Phosphide and Related Materials (IPRM). [Extracted from the article]

The numerical simulation of the light transmission through the device shows that the MMI loop reflector provides 45% and 80% higher absorption values in comparison with a waveguide end reflector and the straightforward transmission, respectively. The scheme includes quantum mechanical and molecular dynamics modelling and Monte Carlo simulation of ion and electron dynamics considering the crystal structure. Morozov et al. SP [ sp 5 SP ] sp covers the modelling of oxide-based memristive elements in the framework of a complex simulation model of an analogue self-learning spiking neural network. [Extracted from the article]

Herein, a simple thermodynamic approach using the Helmholtz free energy is proposed to estimate the noninteger valence in Ce‐based compounds at the γ→α phase transition. The idea of an electron phase transition within Anderson–Kondo model is used as a microscopic mechanism and applied to Ce–X (X = Y, Al–Sc) within 0–16 at% of X. In the suggested approach, valence of Ce–X compounds depends on volume collapse and the temperatures of start and finish of phase transition as well as external pressure, which can induce γ→α phase transition, and increases with rising the amount of impurity. [ABSTRACT FROM AUTHOR]

In their last article [Phys. Lett. A 2021, 389, 127091], the authors have extended the k⋅p approach by considering crossings with the spin–orbit interaction (SOI) up to the second order and studied the spin texture and Berry phase of the heavy‐mass holes (HHs) confined in the SiGe 2D quantum well system. HHs cause quasi‐degeneracy via the intersub‐band interaction (ISI) working as Dirac‐like singularity, leading to the energy‐dependent Berry phase "quantized" by π. This π quantization is understandable by counting the number of quasi‐degenerate points in the Brillouin zone alongside recognizing the sign of the Berry curvature there. Herein, the remaining holes of the light‐mass holes (LHs) and separate holes (SHs) are studied. The spin textures and the Berry curvatures and phases are explored comprehensively, focusing on the competition between the Rashba and Dresselhaus SOIs via ISI. Comparisons with HHs elucidate that LHs and SHs cause similar quasi‐degeneracy through ISI, functioning as the Dirac‐like singularity. As such, the Berry phase is quantized by π, confirming the validity of the counting model irrespective of hole type. In some peculiar cases, HHs and LHs cause a possible sign inversion in the Berry phase, leading to zero Berry phase against temperature. [ABSTRACT FROM AUTHOR]

Herein, thermomagnetic properties of a ferro‐ferrimagnetic system with magnetic moments of values Q=±7/2,±5/2,±3/2,±1/2, and S=±3/2,±1/2 alternating on a square lattice, are investigated. These properties are framed in hysteresis, double‐spin compensation, and discontinuous behavior of the system. Through Monte Carlo simulations, the temperature dependence of the magnetization and magnetic susceptibility of the system for zero and nonzero values of an applied external magnetic field are analyzed. The hysteresis behavior of the model for different temperature values is also studied. It is found that the system experiences double‐spin compensation and multiple hysteresis loops when it is subjected to different values of single‐ion anisotropy and magnetic fields. The increase in the strength of the magnetic field generates discontinuities in the magnetization, and the inversion of its polarity destroys the compensation points. Finally, a phase diagram is presented with the critical, spin compensation, and discontinuous temperatures in terms of the magnetic and anisotropic fields for the ferri‐ and ferromagnetic cases. The results are compared with a recent investigation of this system that does not include the antiferromagnetic next‐nearest‐neighbor interactions, which influences the magnetic behavior of the model. [ABSTRACT FROM AUTHOR]

The present study uses a full‐potential linearized augmented plane wave method and Bethe–Salpeter equation to calculate and interpret the optical properties of Sc2CT2 (T = O, F, and OH) and Hf2CO2 MXene semiconductors, including real and imaginary parts of the dielectric function along with energy loss function. Excitonic structures are observed below calculated bandgaps in these compounds. Sc2CO2 and Sc2CF2 have three excitonic features, whereas Sc2C(OH)2 and Hf2CO2 show two. As compared to other compounds, Sc2CO2 has a larger exciton binding energy. The energy loss functions display spectral features near the bandgap regions due to the excitonic structures in the imaginary part of the dielectric function. [ABSTRACT FROM AUTHOR]

Herein, a mechanism is proposed as to how thin films formed from a Heusler compound can simultaneously have both perpendicular magnetic anisotropy (PMA) and be half‐metallic. It is proposed that a thin film formed from a half‐metallic full‐Heusler or half‐Heusler compound that is cubic in the bulk can undergo a tetragonal distortion by adopting the lattice constant of the underlayer material during the thin film deposition process. The value of this distortion can be tuned by using underlayer materials with different in‐plane lattice constants. The distortion can thereby be optimized so that it is large enough to give rise to sufficient PMA, while, simultaneously, small enough to retain the half‐metallic properties (and, therefore, high tunneling magnetoresistance properties) of the Heusler compound. Density functional theory (DFT) calculations that are carried out for 90 full‐Heuslers and 147 half‐Heuslers that have been identified in the literature as half‐metals show that of these, 14 full‐Heusler and 59 half‐Heusler compounds display both half‐metallicity and PMA for optimal tetragonal distortions. [ABSTRACT FROM AUTHOR]

Herein, periodic density‐functional theory calculations for both bulk and monolayer structures of the getchellite (AsSbS3) compound are reported. The experimental crystal structure is modelled with partial occupations by using a supercell, the resulting structure being found to be dynamically stable. The Perdew–Burke–Ernzerhof (PBE) and Heyd–Scuseria–Ernzerhof (HSE) calculations show that AsSbS3 is a semiconductor with an indirect bandgap of 1.62 and 2.30 eV for the bulk structure, and of 1.90 and 2.64 eV for the monolayer. Also, it is identified that the conduction band minimum is mostly due to the contribution of p‐As, p‐Sb, and s‐S orbitals, while the valence band maximum corresponds mainly to the contribution of p‐S orbitals. [ABSTRACT FROM AUTHOR]

Amorphous carbon nanotubes (a‐CNT) with up to four walls and sizes ranging from 200 to 3200 atoms have been simulated, starting from initial random configurations and using the Gaussian Approximation Potential. The important variables (like density, height, and diameter) required to successfully simulate a‐CNTs were predicted with the machine learning random forest technique. The width of the a‐CNT models ranged between 0.55–2 nm with an average inter‐wall spacing of 0.31 nm. The topological defects in a‐CNTs were analyzed and new defect configurations were observed. The electronic density of states and localization in these phases were discussed and delocalized electrons in the π subspace were identified as an important factor for inter‐layer cohesion. Spatial projection of the electronic conductivity favors axial transport along connecting hexagons, while non‐hexagonal parts of the network either hinder or bifurcate the electronic transport. A vibrational density of states was calculated and is potentially an experimentally comparable fingerprint of the material. The appearance of a low‐frequency radial breathing mode was discussed and the thermal conductivity at 300 K was estimated using the Green‐Kubo formula. [ABSTRACT FROM AUTHOR]

Magnetoelectroporation is an effective method of opening nanopores in cell membranes using magnetoelectric nanoparticles (MENPs) for the purpose of in vivo and in vitro delivery of drug substances to cancer cells. A microscopic approach is proposed as theoretical basis for that phenomenon. The underlying Hamiltonian includes the magnetic and ferroelectric subsystems characterized by two‐order parameters. The related magnetoelectric coefficient αHE characterizes the relationship between the applied magnetic field and a generated local electric field. Whereas the spontaneous polarization P→S of the MENP is due to the arrangement of electric dipoles, there appears an additional spin‐assisted polarization ΔP→ owing to the magnetic phase transition. It is shown that the main contribution to the local field comes from P→S. Moreover, the local electric field depends on the orientation of the easy‐axis magnetization of the MENPs with respect to applied external magnetic field. The magnetoelectric coefficient exhibits a nonlinear dependence on the external magnetic field. The results are based on an analytical Green's function method. The numerical calculations are performed for spherical, structurally heterogeneous nanoparticles composed on a core and a shell, where the noninteracting nanoparticles have the same diameter of 25 nm. The results are in qualitative agreement with experimental observations. [ABSTRACT FROM AUTHOR]

Herein, the series‐connected Josephson transmission line (JTL), constructed from Josephson junctions, capacitors, and (possibly) resistors, is considered. It is shown that the compact travelling waves in the lossy JTL are the shocks, some of their properties including their velocity are studied. The velocity of shocks in the discrete lossy JTL is calculated. The continuum, the quasi‐continuum, and the quasi‐discrete approximations for the discrete JTL, both lossless and lossy, are thoroughly studied. In the framework of the latter, it is shown that the only compact travelling waves in the lossless JTL are the kinks and the solitons. On top of the continuum and the quasi‐continuum approximations, the simple wave approximation, which decouples the JTL equations into two separate equations for the right‐ and left‐going waves, is proposed. The approximation, in particular, allows to easily consider the formation of shocks in the lossy JTL. [ABSTRACT FROM AUTHOR]

A study, within the path probability method, of the dynamic magnetic features of the mixed spin (2, 5/2) Ising ferrimagnetic system on a hexagonal lattice under the presence of a sinusoidal external magnetic field is presented. The Hamiltonian of the system contains intersublattice, intrasublattice, and crystal‐field interactions. The intersublattice interaction is taken as antiferromagnetic. The time variations of average dynamic magnetizations and the thermal behavior of the dynamic magnetizations are investigated to obtain the phases in the system and to characterize the nature of the dynamic phase transitions and find the dynamic phase transition temperature points. The dynamic phase diagrams in six different phase planes are presented, in which they contain the paramagnetic (p) phase, three different ferrimagnetic (i1, i2, i3) fundamentals, and the p + i1, i1 + i2, and i2 + i3 mixed phases as well as the dynamic tricritical point and the dynamic double critical end point, depending on the interaction parameters. The dynamic compensation behavior is also examined and only N‐type behaviors are observed. Some of the obtained dynamic phase diagrams are in qualitatively good agreement within some works on the dynamics of mixed‐spin Ising system. [ABSTRACT FROM AUTHOR]

As an effective description of general open systems, the non‐Hermitian (NH) Hamiltonians have attracted much attention recently. New topological properties unique to NH have been discovered. Herein, the one‐dimensional NH systems in the presence of particle–hole symmetry are considered and demonstrate that the topological phase transition happens when the momentum of E=0 states touches the unit circle of the generalized Brillouin zone. This criterion is in agreement with the critical point that zero modes are annihilated into the continuum bands, i.e., the gap of continuum bands is closed. This criterion of phase transition is also verified for the models of the Kitaev chain and Alicea nanowire, by introducing two NH terms including the Hatano–Nelson term and complex chemical potential. It is found that the skin effect enhances the localization of zero modes. Moreover, the NH Kitaev chain and Alicea nanowire with electric circuits for further experiments are realized. [ABSTRACT FROM AUTHOR]

The influence of crystal structure on the phonon modes and electron–phonon coupling properties in nitride quantum ring (QR) structures is investigated based on the macroscopic dielectric continuum model. It is found that three types of phonon modes including the surface optical (SO) phonon modes, the exact confined (EC) modes, and quasiconfined (QC) modes can coexist in the wurtzite nitride QR. However, only the SO modes and EC modes may appear in zinc‐blende nitride QR, and the QC modes cannot exist in zinc‐blende QRs in general. Numerical calculation on AlN QR shows that the SO modes of zinc‐blende QR are more dispersive than those of wurtzite QR. Furthermore, the degenerative behavior of QC modes to SO modes in wurtzite QRs is clearly observed. Moreover, the electron–phonon coupling functions in zinc‐blende QRs are larger than those in wurtzite QRs. These results reveal that the crystal structures greatly affect not only the type of phonon mode, but also the coupling strength of electron–phonon interaction. The present theoretical scheme and the numerical results are quite useful and important for further understanding and investigating the polaronic effect and related physical properties in wurtzite and zinc‐blende nitride QRs. [ABSTRACT FROM AUTHOR]

Based on an envelope function approach pioneered by Wannier and Slater, it can be shown that under the influence of strong effective magnetic fields in spinor space the band structure of certain materials gives rise to the analogs of tardyons and luxons, and in principle also to the analogs of tachyons. Such a (hypothetical) tachyonic band structure would be metallic, but with a gap in k‐space and not in the range of allowed band energies En(k). Some of the conditions to observe such a tachyonic anomaly in certain types of electronic band structures, which do not seem to be implausible, are discussed. Similar anomalies should appear in the spectrum of Landau levels. Furthermore, some of the pathologies that would come with such exotic band structure anomalies are pointed out. [ABSTRACT FROM AUTHOR]

This work describes a series of investigations carried out on sets of pristine and auxetic (negative Poisson's ratio (NPR)) open‐cell polyurethane foams subjected to relative humidity (RH) conditioning ranging from 9% to 92% at room temperature. The foams have been produced using a uniaxially thermoforming process. Pristine and auxetic foams have then been subjected to quasi‐static compressive cyclic loading (with maximum strains of 10% and 80%, respectively), as well as vibration transmissibility tests with base accelerations up to 2.29 g. Increasing levels of RH do not seem to statistically affect the moduli and PRs of foams subjected to lower maximum strains, however, especially the auxetic foams at higher compressive deformations show a decrease in the stiffness with the increase of the RH. The vibration tests show an increasing trend of the dynamic modulus of the foams with the increase of the RH. The results indicate the complexity of the interaction between foam architecture and absorption/desorption mechanisms occurring inside these porous auxetic materials. [ABSTRACT FROM AUTHOR]

Wooden sandwich panels with a corrugated core have not been the subject of scientific research so far. The anisotropic properties of the wood make it challenging to form corrugated shapes. Therefore, it is decided to determine the effect of geometric imperfections of the corrugated core made of wood veneers on the stiffness and strength of sandwich panels and the core elasticity modulus. The beams are manufactured in industrial conditions and subjected to three‐point bending. The research is carried out in the form of tests and numerical calculations. It is demonstrated that geometric imperfections of the core affect the stiffness and strength of sandwich panels. The modulus of elasticity can reach values lower by up to 37% and the strength by up to 24% compared with reference panels with an ideal, symmetrical core geometry. However, their average linear elasticity modulus (1449 MPa) indicates excellent construction properties. Under the tests, four stages of beam bending are revealed. The last stage means that panels can increase stiffness even after the core is destroyed. The corrugated core's modulus of elasticity is also determined. [ABSTRACT FROM AUTHOR]

Cellular solids whose ligaments are made of two distinct materials are constructed for studying their auxeticity and negative thermal expansion via 2D models with the methodology of finite‐element numerical analysis. Three bimaterial cellular models with various radii of ligament curvature (Rc = 5, 8, 11 cm) are analyzed. It is found that when the ligaments comprise aluminum and titanium alloy with Rc = 5 cm, the cellular solid exhibits simultaneous negative effective Poisson's ratio (−0.418) and negative thermal expansion coefficient (−20.82 × 10−6 K−1). When the radius of ligament curvature increases, auxeticity is less pronounced. Positive and negative thermal expansion can be tuned solely by the coefficients of thermal expansion of ligaments' constituents. Furthermore, smaller radii of curvature give rise to larger negative thermal expansion. In addition, modulus mismatch in the bimaterial ligament can be used to tune overall properties. Our findings herein may serve as foundations for the future quantitative design of such cellular materials. In addition, effective Poisson's ratio and coefficient of thermal expansion can be positively or negatively enhanced due to the interplay between the positive and negative phases. Interactions between negative stiffness and larger curvatures may make the system less unstable. [ABSTRACT FROM AUTHOR]

The utility of auxetic materials in applications such as foams and composites is contingent upon the performance of these materials under cyclic loading. Recently, several textile materials (knitted, woven, and nonwoven fabrics) have been found to exhibit auxetic properties, either through design and/or the use of a postprocessing treatment. In the wake of these advancements, this research examines the reversibility of the out‐of‐plane auxetic response in previously studied polyester fiber needle‐punched nonwovens. Herein, a heat‐compressed nonwoven is strained cyclically to different levels, and the thickness is measured before and after straining. While axial extension is found to be elastic for up to 3% strain, thickness increases (auxetic responses) are almost completely reversible for 1% axial strain and highly reversible for 2% and 3% axial strain. Irreversible changes can be clearly observed starting at strains of 2% and larger, especially for a higher number of cycles. Combining these results with the previous understanding from microscopic and tomographic imaging, possible reversible (straightening of bent fibers and fiber bundles) and irreversible (slipping or breaking of fibers) structural deformations leading to thickness changes are identified. These processes influence the magnitude of the auxetic response within and beyond the elastic strain regime, respectively. [ABSTRACT FROM AUTHOR]

An auxetic metamaterial based on a semirotation system is designed herein by combining rigid units of two different shapes, such that each unit cell consists of one nonrotating rhombus and four rotating right triangles. The on‐axes Poisson's ratios are obtained for both infinitesimal and finite deformations by geometrical consideration. The on‐axes Young's moduli of this metamaterial are established by matching the spring potential energy stored at the hinged joints with the strain energy of deformation for the homogenized continuum of the metamaterial. Plotted results describe the interlacing effect of the shape descriptor, the original separation angles, and the change in the separation angle on the on‐axes Poisson's ratio and Young's modulus. The latter is directly proportional to the equivalent spring stiffness per unit cell. In addition to attaining auxetic behavior, this metamaterial can also be designed to achieve specific Young's modulus behavior including extreme stiffness in one of the directions either at infinitesimal or finite deformation. [ABSTRACT FROM AUTHOR]

The gyroid lattice is prepared in chiral and non‐chiral forms. The chiral gyroid lattice is observed to exhibit temperature‐induced twist with the direction of twist corresponding to the sense of chirality. This effect is a nonclassical effect that cannot occur in classical elasticity or classical thermo‐elasticity but is allowable in Cosserat solids. Poisson's ratio of the gyroid is known to be about 0.3 with minimal dependence on size. In contrast to squeeze–twist coupling in which substantial size effects occur with slender specimens twisting much more than thicker ones, thermal–twist coupling exhibits opposite and less consistent size effects of much smaller magnitude. [ABSTRACT FROM AUTHOR]

Life‐changing illnesses and fatalities caused by inefficient personal protective clothing and equipment are increasing day by day. The discrepancy between the test standards, environmental conditions, and infield collision is the reason why personal protection equipment and clothing have not yet decreased the number of injuries in various fields such as military and sports. To further increase the efficiency of personal protection materials, auxetic materials are suggested because of their high energy absorption, good permeability, form‐fitting ability, and high indentation resistance. Auxetic materials are nonconventional materials with a negative Poisson's ratio and can shrink under compression and expand when subjected to stretching. In comparison to nonauxetic conventional materials, auxetic materials have improved properties that can be useful for personal protection applications. This review focuses on the importance of auxetic materials for personal protection, focusing on reducing the chances of injury and what possible ideas can further benefit the protection products. The first part of the review discusses the auxetic structures and their protection applications followed by the fabrication of auxetic structures. The review will conclude with limitations, economic prospects, and what possible work can further improve the potential use of auxetic materials in personal protection. [ABSTRACT FROM AUTHOR]

The phase composition and magnetic properties of FeNi nanoparticles encapsulated in carbon with a nickel content of about 10% are studied in comparison with FeNi nanoparticles of similar composition without carbon coating. The Fe91Ni9 particles have the body centered cubic structure, whereas the Fe88Ni12@C particles have the face centered cubic (FCC) structure. The Fe88Ni12@C particles are characterized with a rather high magnetization of 60 emu g−1 in the field of 30 kOe at 5 K and 40 emu g−1 at 300 K. The monotonous behavior of magnetization with temperature gives grounds to assume that the Fe88Ni12@C particles retain the FCC structure over the entire temperature range down to 5 K. It is concluded that the stabilization of FCC phase of Fe88Ni12@C and the ferromagnetic state of this FCC phase are related to a large concentration of carbon in the core of the nanoparticles. [ABSTRACT FROM AUTHOR]

The goals of this study are to use density functional theory to study the core structure energetics of the 30° and 90° partial dislocations in HgTe, CdTe, and Hg0.7Cd0.3Te as well as the density of states of these dislocations in CdTe and Hg0.7Cd0.3Te. For the 30° partial dislocations, two stable dislocation pairs were found. The pair with a double‐periodic α‐core (Te) dislocation and a single‐periodic β‐core (Hg/Cd) dislocation was found to be the most stable out of the two for the simulation sizes tested. For the 90° partial dislocations, two stable dislocation pairs were also found. The first has a single‐periodic β‐core dislocation and a single‐periodic α‐core dislocation, whereas the second has a double‐periodic β‐core dislocation and a single‐periodic α‐core dislocation. The most stable out of the two depends on the simulation size tested. For both of these partial dislocations in Hg0.7Cd0.3Te, it was found that it is energetically favourable for Hg atoms to segregate to the dislocation cores. Furthermore, in CdTe and Hg0.7Cd0.3Te, it was found that the 90° partial dislocations are likely to be more detrimental to the material optoelectronic properties since they introduce more mid‐gap states within the band gap in comparison to the 30° partial dislocations. [ABSTRACT FROM AUTHOR]

The layered perovskite compounds, which show multiferroic properties, have attracted interest due to their interesting magnetic and electronic properties. Herein, the heat capacity of EsBaCuFeO5 (Es = Ho, Gd and Yb) as a function of the temperature using the overall equation of fitting is investigated. The Debye temperature, Einstein temperature, the coefficients m and γ are derived by fitting experimental heat capacity data with the overall equation of fitting that consists of the contribution from electronic, Debye, and Einstein terms. The values of the fitting parameters obtained are in good agreement with the results in the literature. The results display that the method can be used for calculation of the heat capacity of the layered perovskite compounds over the entire range of temperature. [ABSTRACT FROM AUTHOR]

The multiferroic properties of BiCrO3 (BCO) bulk and thin films are investigated for the first time using a microscopic model. The influence of ion doping on the multiferroic properties of BCO is also studied because the doping process changes the physical properties and can be used for potential applications in magnetoelectronic devices. The magnetization M increases by Mn and decreases by Ga‐ion doping whereas the Néel temperature TN decreases in both cases. There are some discrepancies by polarization whether it is ferroelectric or antiferroelectric. It is shown that bulk pure BCO is antiferroelectric because the electric field dependence of polarization P shows a double hysteresis loop and the dielectric constant has no anomalies at TN. In Ga‐, Mn‐ or Ti‐doped BCO a ferroelectric polarization appears. The specific heat shows a peak at TN for BCO. By Ga doping, this peak vanishes with increasing x. The multiferroic behavior of BCO is demonstrated in the magnetic field dependence of the dielectric constant. In BCO thin films, ferroelectric and ferromagnetic behavior is observed. [ABSTRACT FROM AUTHOR]

A promising strategy to tailor the magnetic and electronic properties of 2D van der Waals magnets is to integrate them with a ferroelectric (FE) substrate. Herein, the FE substrate effect of BiFeO3(0001) with different surface terminations is explored using density functional theory calculations for the ferromagnetic 2H‐VS2 monolayer. It is observed that depending on the polarization direction and surface termination of the BiFeO3(0001) FE substrate, the 2H‐VS2/BiFeO3(0001) interface exhibits a substantially varied charge transfer behavior. The magnetic and electronic properties of the monolayer 2H‐VS2 are significantly modulated by the interface charge transfer. Furthermore, in the 2H‐VS2/BiFeO3(0001) heterostructures, large interface magnetoelectric coupling coefficients are predicted. The in‐plane magnetic and electronic properties of monolayer 2H‐VS2 can be effectively tuned by the out‐of‐plane FE polarization, paving the way for a novel class of spintronic devices based on the 2H‐VS2/BiFeO3(0001) hybrid system. [ABSTRACT FROM AUTHOR]

Phase‐change material Ge2Sb2Te5 (GST) is a promising candidate for nonvolatile photonic devices due to its phase stability, different absorption coefficients in the amorphous and crystalline phase, and relatively fast response. Here, an energy‐efficient design of a photonic nonvolatile memory that stores its logical status as GST phase states is proposed. The device is based on the silicon‐on‐insulator (SOI) substrate and consists of the fourfold symmetric strip waveguide crossing incorporated with the square GST patch and a multimode interference (MMI) loop reflector. The distinctive feature of the proposed cell is two spatially separated recording/erasing and readout channels. One of the crossed waveguides is connected to the MMI loop reflector and used for recording/erasing. The other waveguide is used for readout. The numerical simulation of the light transmission through the device in question shows that the MMI loop reflector provides 45% and 80% higher absorption values in comparison with waveguide end reflector and straightforward transmission, respectively. This fact allows the more efficient utilization of the guided mode energy and makes the proposed photonic memory cell an attractive node element for photonic integrated circuits. [ABSTRACT FROM AUTHOR]

The localized running waves in the discrete Josephson transmission lines (JTL), constructed from Josephson junctions (JJ) and capacitors, are analytically studied. The quasicontinuum approximation reduces calculation of the running wave properties to the problem of equilibrium of an elastic rod in the potential field. Making additional approximation, the problem is reduced to the motion of the fictitious Newtonian particle in the potential well. It is shown that there exist running waves in the form of supersonic kinks and solitons and their velocities and profiles are calculated. It is shown that the nonstationary smooth waves which are small perturbations on the homogeneous nonzero background are described by Korteweg–de Vries equation and those on zero background by modified Korteweg–de Vries equation. The effect of dissipation on the running waves in JTL is also studied and it is found that in the presence of the resistors, shunting the JJ and/or in series with the ground capacitors, the only possible stationary running waves are the shock waves, whose profiles are also found. Finally, in the framework of Stocks expansion, the nonlinear dispersion and modulation stability in the discrete JTL are studied. [ABSTRACT FROM AUTHOR]

Herein, the crystal structure, surface morphology, and magnetic and thermal properties of the BaFe11.9In0.1O19‐substituted M‐type hexaferrite are investigated. This solid solution is fabricated using "two‐step" topotactic reactions. It is determined through the X‐ray diffraction method that the crystal structure of this solid solution under normal conditions has hexagonal symmetry with P63/mmc space group (No. 194) with the unit cell parameters a = 5.8992(1) Å and c = 23.2275(7) Å. It is determined by the scanning electron microscope (SEM) researches that the average size of the grains is d¯ = 6 μm. It is determined by the vibration magnetometry that the ferrimagnet–paramagnet phase transition happens at around TC = 420 °C. Using differential scanning calorimetry (DSC), it is found that air and water molecules leave the sample surface up to 420 °C and the resulting oxygen anions appearing as a result of a solvothermal reaction fill the oxygen vacancies in the crystal structure at high temperatures up to 800 °C. The thermal transitions repeated in the high temperatures are established. The oxidation behavior of this compound is determined from thermogravimetric analysis (TGA) in a wide temperature range. [ABSTRACT FROM AUTHOR]

Present investigation rigorously explores the time‐average excitation rate (TAER) of ground‐state electronic population of GaAs quantum dot (QD) to the excited eigenstates. The QD confinement potential contains Gaussian impurity (the dopant) and Gaussian white noise (GWN). GWN can be categorized as either additive or multiplicative depending upon its way of attachment to the doped QD. The excitation occurs as soon as the noise strength begins fluctuating with time in periodic or random manner. The study highlights the coupled influence of the varying physical quantity, presence/absence of noise, the mode of attachment of noise to QD, and the nature of time‐fluctuation of the noise strength (periodic/random), and finally harnesses and tailors the features of the TAER profiles. The TAER plots unveil steady rise, steady fall, maximization (linked with the emergence of large nonlinear optical response), minimization, and saturation (linked with dynamic freezing). The findings appear to be significant in the practical usage of QD‐based devices. [ABSTRACT FROM AUTHOR]

Cluster‐based crystals containing the (Nb6Cl12)2+ or (Ta6Cl12)2+ clusters, including the well‐known Nb6Cl14, K4Nb6Cl18, and the Prussian blue analog (Me4N)2 [MnNb6Cl12(CN)6], have been investigated by density functional theory. The electronic structure of the cluster is the same for all compounds, with a semiconducting gap of around 1 eV between occupied and empty states, in the range of interest for solar energy applications. Calculations suggest that these clusters could be used as cations in hybrid organic–inorganic perovskites, as a substitute for toxic Pb2+. Moreover, bandgaps, band alignment, and hydrogen adsorption calculations show that the designed cluster‐based hybrid perovskites have potential as intermediate band materials for photovoltaics, and as photocatalysts for the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

Graphite oxide (GrO) and 2,3‐diaminomaleonitrile‐doped GrO (GrODAMN) materials are synthesized by the modified Hummers method. Oxidation and N‐doping treatments increase the C/O ratio from 2.49 to 2.88 for GrO and GrODAMN materials, respectively. GrODAMN material shows higher thermal resistance from room temperature to 800 °C compared with GrO material. Furthermore, the hydroxyl, epoxy, and carboxyl vibrational bands observed for GrO are masked after N‐doping and the intensity of the D‐band increases with respect to the intensity of the G‐band. These changes in dipole moment and polarizability of the molecules are associated with defects and disorders in the carbon lattice, which modify the microstructure order caused by the creation of carbon–nitrogen functional groups. GrODAMN material shows 6.14 atomic % nitrogen associated with imine, amide, and/or imidazole functional groups formed during N‐doping. High‐resolution transmission electron microscopy micrographs show polycrystalline regions with irregular polygons, where the interaction between layers of both materials is dominated by van der Waals forces and electrostatic interactions, showing interplanar distances of 3.35 and 7.39 Å. Finally, GrODAMN shows a specific pseudocapacitance value 49% higher than for the GrO material, associated with less reversible processes in redox reactions. [ABSTRACT FROM AUTHOR]

Precipitated phases, formed by spinodal decomposition during long‐term storage in a desiccator in dry atmosphere, are found with the X‐ray diffraction (XRD) study of Fe1+yTe1−xSex crystals. Their compositions are deduced from the position of satellite Bragg reflections in the XRD pattern. In particular, in the Fe1.19Te0.58Se0.42 crystal, traces of phases with significantly higher tellurium content, namely Fe1+yTe0.9Se0.1 and FeTe, are found. The detection and analysis of side bands in the diffraction pattern of an aged crystal indicate spinodal decay. It leads to the formation of a modulated structure in the entire volume of the sample and to strain in the crystal structure. In turn, this results in a significant improvement in the superconducting characteristics. Specifically, the resistive transition narrows to 2 K at the onset temperature 14.5 K, and the superconducting volume fraction increases up to about 100%. [ABSTRACT FROM AUTHOR]

First‐principles molecular dynamics calculations are performed to investigate the reactions of hydrogen and calcium carbonate melts at pressure–temperature conditions appropriate to the Earth's lower mantle and core–mantle boundary. Two models with different hydrogen‐to‐carbonate ratios are studied. A variety of chemical reactions are observed. It is found that hydrogen dissociates readily and reacts with free carbonate anions forming various transient chemical species and water molecules. Further reactions of these reactive species serve as intermediates to form C–C and C–O connections. The unreacted bulk carbonates are linked via polymeric‐cornered shared CO4 tetrahedra. At 110 GPa and 4087 K, "diamondoids" with tetrahedral C4 moieties are found. The theoretical results support recent reports on the observation of tetrahedra CO4 in high‐pressure carbonate glasses and suggest a plausible explanation of ice VII inclusion in deep‐Earth diamonds. [ABSTRACT FROM AUTHOR]