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The analytical solution of an elliptic dielectric cavity in an infinite dielectric plate is taken as basis to investigate a Griffith crack problem which is obtained by letting the semi-minor axis tend towards zero. In the course of this, an erroneous conformal mapping, commonly employed in literature and correctly reproducing the electric field only in a part of the physical space, is rectified. Interpreting the elliptic interface as faces of a mechanically opened crack which is exposed to an oblique remote electric field, surface charges and electrostatic tractions are calculated. In contrast to the established capacitor analogy model, approximately yielding electric charge densities and Coulombic tractions from displacements and electric potentials in the undeformed crack configuration, the work at hand provides exact solutions accounting for different implications of the crack curvature and for the inclination of the electric field. Crack weight functions are finally used to calculate stress and electric displacement intensity factors. As turns out, the surface charges of the capacitor analogy represent an excellent substitute for the exact electric boundary conditions within a relevant range of parameters, whereas inaccurate Coulombic tractions in the vicinity of crack tips may lead to a significantly overestimated mode I stress intensity factor. [ABSTRACT FROM AUTHOR]

Uncovering new ways for light localization at the micro‐ and nanoscale is essential for the development of state‐of‐the‐art photonic devices. Nowadays the most advances in this area are achieved using near‐field resonators, providing extreme light confinement in nanoscale volume. However, the boosting of device performance in some practical applications, for example, luminescent sensing, optical tweezing, and super‐resolution optical microscopy require light localization at distances beyond near‐field range. This issue can be addressed by employing dielectric microstructures that produce photonic nanojets (PNJs), representing an intermediate state between near‐field localization and geometric optics. Despite the promising benefits of PNJ implementation in various optical applications, their practical studies are scarce and mostly limited to numerical simulations. Here, a new type of PNJ is introduced and studied both numerically and experimentally. Contrary to the conventional case, wherein PNJ is generated by a single microstructure, the reported PNJ is produced through collective effects in a densely packed array of dielectric microstructures. The studies reveal that these collective PNJs can reach an unprecedented length of >60 λ, while maintaining a high localization intensity. Under certain configurations of the array, collective PNJ can enhance the electromagnetic field by up to sevenfold, being a versatile tool for various photonic applications. [ABSTRACT FROM AUTHOR]

This paper investigates the hydrothermal behavior of leaky dielectric and perfect dielectric droplets impacting a superheated wall within a specific range of Weber numbers (We≤30) $(We\le 30)$ under an electric field. Through this investigation, we aim to provide a more comprehensive understanding of the dynamics involved in droplet‐superheated surface interactions under electric fields, which can be useful in various applications, such as the design of cooling systems and combustion chambers. The study utilizes the level‐set and ghost fluid techniques to capture the interface accurately. Under an electric field, different behaviors are observed during the impact process, depending on the electrical properties of the droplet. A perfect dielectric droplet experiences a reduction in spreading extent and an increase in contact time. However, no remarkable enhancement in total heat removal occurs in this case. For the leaky dielectric droplet exhibiting prolate deformation at the stationary state, increasing the electric field magnitude results in a slight decrease in the droplet spreading extent, while the droplet contact time and total heat removal from the surface increase. At an electric capillary number of 1.55E − 2 and a Weber number of 25, the enhancement in the contact time and total heat removal is about 43% and 15%, respectively. For the leaky dielectric droplet with oblate deformation at the stationary state, the spreading extent and total heat removal increase, with negligible changes in contact time. At the above‐mentioned electric capillary and Weber numbers, the enhancement in the spreading extent and total heat removal is about 7.5% and 15%, respectively. [ABSTRACT FROM AUTHOR]

In the present study, SrTiO3 was selected to enhance the multiferroic characteristics of Bi0.88Sm0.12FeO3 (BSF) ceramics. With increasing SrTiO3 content, the principal phase of BSF ceramic transitions from rhombohedral R3c to Pna21. Through DSC and dielectric analysis, it was observed that both the Curie temperature and Néel temperature decreased proportionally with the augmentation of SrTiO3 content. When x =.1, the optimal ferroelectric performance is achieved, and the highest remanent polarization value is 55.47 µC/cm2, significantly surpassing that of BSF ceramics. Moreover, the PFM test results showed that as the substitution content increased, the domains in the BSF ceramic gradually transformed from normal ferroelectric domains to polar nanomicro‐domains. Magnetic and magnetoelectric results show that when x =.1, the best magnetic properties are obtained, Mr = 59.7 emu/mol. The magnetoelectric coefficient αME initially increased and then decreased with the increasing SrTiO3 content, reaching its optimum magnetoelectric properties at x =.1, where αME =.47 mV cm–1 Oe–1. In summary, when the substitution amount of SrTiO3 reaches 10%, the ferroelectric, magnetic, and magnetoelectric properties of BSF ceramics are significantly improved. [ABSTRACT FROM AUTHOR]

Dielectric spectroscopy is widely used in research on electronic materials. When processing experimental data, relaxation models are often used to obtain the parameters of the researched material. However, we should prefer the oscillator methods to study composite materials with resonance components, crystals, and polycrystals, whose structure is multi-domain or characterized by high disharmony. In this paper, we consider a dielectric dispersive oscillator model in detail. Primary attention is paid to the case of an oscillator with very high attenuation. It is determined that the main feature of resonance dispersion is the presence of a minimum in the frequency dependence of a real part of the permittivity. [ABSTRACT FROM AUTHOR]

A tunable plasmonic filter in the near-infrared range is being investigated using the finite element numerical method (FEM). The filter structure consists of a serrated dielectric layer, which includes an air layer and silica teeth sandwiched between two metal layers. A numerical analysis shows that it is possible to adjust the band-stop amplitude, intensity, and band-pass width by changing the geometrical parameters. The proposed structure is expected to be used as an essential component of photonics devices due to its ability to confine light in the sub-wavelength region. [ABSTRACT FROM AUTHOR]

This paper reports the design of ferroelectric nanowires using HfO2 and Al2O3. Ferroelectric nanowire transistors have drawn considerable attention recently because of their potential for use in low-power devices and non-volatile memory systems. In this work, the drain current, acceptor concentrations, and electric field are analyzed. The results obtained for the proposed device structure highlight the relevance of Al2O3- and HfO2-based nanowires as potential materials for the development of cutting-edge nanotechnology and materials science advancements. The proposed device structure has ION = 3.8 × 10−5 using HfO2 and ION = 3.48 × 10−4 using Al2O3. The significant improvements in the results make ferroelectric nanowire interesting for the scientific and research community working in this area. [ABSTRACT FROM AUTHOR]

The generalized Poisson–Boltzmann equation with the uniform ionic size is investigated. In mean-field theory, the ionic size effect is added by modifying the entropy effect of solvent molecules in the electrostatic free-energy functional of ion concentrations. Taking minimization of the mean-field electrostatic free-energy functional including the ionic size effect with respect to the ion concentrations, the minimum free-energy is obtained (see (4.6) in Li [(2009a) "Continuum electrostatics for ionic solutions with non-uniform ionic sizes," Nonlinearity 22(4), 811–833]. Maximizing the minimum free-energy with respect to the electrostatic potential determines the generalized Poisson–Boltzmann equation. By the definition of shape derivative, the first variation of this minimum free-energy with respect to variation of the dielectric boundary is derived. Thus, the dielectric boundary force of an ionic solution with multiple ionic species with the uniform ionic size is obtained. [ABSTRACT FROM AUTHOR]

The solution-processed organic thin-film transistors (OTFTs) with a minimal device footprint and improved performance are desirable for flexible electronics and other circuit applications. It is demonstrated that the enhanced performance can be achieved for solution-processed OTFTs by adopting an improved Corbino structure. The bottom-gate bottom-contact OTFTs of W/L ratio of 500 are fabricated using the standard poly-3-hexylthiophene (P3HT) as a semiconductor with an improved interdigitated pseudo-Corbino (IPC) structure. The exhibited IPC structure is a combination of interdigitated structure in the enclosed-Corbino design to achieve infinite output resistance, suppressed parasitic leakage current, and high ON current by accommodating a high W/L ratio in a minimal device footprint. For the fabricated solution-processed OTFTs, infinite output resistance with an OFF-current of the order of 1 0 − 12 A and an ON/OFF ratio of drain current of the order of 1 0 7 is achieved. Incorporating an enhanced hexamethyldisilazane treatment of the Si O 2 gate dielectric improves the ON/OFF ratio to a record value of 1 0 8 and the mobility of the order of 1 0 − 2 cm 2 / Vs for P3HT. Implementation of IPC-TFT structure for intentionally chosen moderate-mobility, solution-processed P3HT semiconductor results in a consistent low OFF-current, high ON/OFF ratio, and infinite output resistance with excellent device-to-device uniformity. [ABSTRACT FROM AUTHOR]

The generation of focused beams in the millimeter- and submillimeter-wave ranges, with transverse-electric (TE) polarization, is investigated in the radiative near-field region. The desired field distribution is achieved through a leaky-wave beam launcher consisting of a grounded dielectric slab with an annular strip grating on top excited by a circular slot on the bottom ground plane. The latter is fed by a Marié transducer, which converts the input, fundamental TE10 mode of a standard rectangular waveguide into the higher-order TE01 mode propagating in the circular waveguide connected to the device. The generation of TE-polarized diffraction-limited Bessel and Bessel–Gauss distributions is achieved by suitably synthesizing the annular strip grating. Simulated results are in excellent agreement with those predicted by leaky-wave analysis providing a proof-of-concept for the generation of TE-polarized Bessel and Bessel–Gauss beams at 300 GHz with a beam size of 1.7 and 1.9 mm up to the nondiffractive range of about 25 and 15 mm from an aperture plane with radius of 12.75 mm, respectively. [ABSTRACT FROM AUTHOR]

Highlights Predicting the dielectric constant of composites based on their component characteristics can accelerate the development of high‐energy storage dielectrics. In this work, to take into account the shape and interaction of randomly oriented inhomogeneities on the dielectric properties of composites, the orientation interaction model (OIM) initially used for composite stiffness prediction is adopted to predict the dielectric constant of composites. OIM applies to multi‐phase composites, and the inhomogeneities are approximated using ellipsoids in OIM. To verify the proposed model, some test data are adopted, and the model predictions match well with the test data. It is found that the inhomogeneity shape has a large influence on the dielectric constant of composites, and the influence increases with increase of the dielectric property difference between inhomogeneities and the matrix. The model captures that at the same inhomogeneity volume fraction, composites containing high aspect ratio inhomogeneities exhibit a high dielectric constant, and it shows penny‐shaped inhomogeneities perform better than cylindrical inhomogenities on increasing the dielectric constant of composites. The interaction among randomly oriented inhomogeneities is considered. Every parameter can be determined based on the microstructure of composites. The proposed model applies to multi‐phase composites. [ABSTRACT FROM AUTHOR]

Uniaxial materials have achieved new prominence in photonics because they can have hyperbolic spectral regions with metallic (ε<0) and dielectric (ε>0) permittivities along different crystal axes. In the lossless case, this results in an open hyperboloid dispersion relation, allowing materials to support highly confined modes with extremely large wavevectors. However, even small losses change the character of the hyperbolic dispersion from open hyperboloids to closed surfaces with finite maximum k, significantly limiting the extent to which highly-confined modes can be achieved. Here, we derive a simple analytic formula for the dispersion relation in the presence of loss and show that for some typical materials the maximum wavevector in hyperbolic materials is roughly ten times the free-space. The scaling of the maximum wavevector is derived, and it is shown that there is a universal scaling relation between the propagation length and the wavelength, which implies that the shortest wavelengths in any hyperbolic material are strongly attenuated. [ABSTRACT FROM AUTHOR]

We numerically demonstrate the creation of Weyl points in a twisted multilayer photonic system. In our system, each layer is anisotropic with plasmonic response along a direction perpendicular to the layer and with anisotropic dielectric response within the layer. We show that Weyl points can be created by controlling the twist angles between the layers so that spatial-inversion symmetry is broken. Compared with existing approaches, our findings offer a potentially simpler structure for creating Weyl points and highlight the prospect of using twisted multilayer systems for achieving topological photonic effects. [ABSTRACT FROM AUTHOR]

Advances in 5G and 6G communication technologies and their applications are in part limited by the capabilities of current electronic packaging materials, as expanded bandwidth is a pressing need for novel dielectric substrates capable of co-firing into packages and devices, characterized by low dielectric loss and enhanced thermal conductivity. This investigation provides further characterization in the dielectric, electrical and thermal conductivity properties over previously reported cold sintered composite of Sodium Molybdate Na 2 Mo 2 O 7 (NMO) with hexagonal Boron Nitride (hBN), such as relative permittivity (ε r) and dielectric loss (tan δ) values at high frequencies of 75–110 GHz, electrical resistivity (ρ) fitting to percolation theory, Weibull statistical analysis of electrical breakdown strength (E b) and its anisotropic thermal conductivity (κ) influenced by the filler's crystal structure. The cold sintered composites were systematically characterized with respect to filler volume fraction, temperature, and frequency. The findings in this analysis position engineered composites as a promising alternative for microwave substrate materials, with using a densification method that limits interactions and maximizes densification, hence the demonstration with cold sintering. [ABSTRACT FROM AUTHOR]

In this contribution, we consider an application of the Kirchhoff migration (KM) technique for fast and accurate identification of small dielectric objects from two-dimensional Fresnel experimental dataset. Generally, for successful application of the KM, a complete set of elements from the so-called multi-static response (MSR) matrix must be collected; however, in the Fresnel experimental dataset, many of the elements of an MSR matrix are not measurable. Nevertheless, the existence, location, and outline shape of small objects can be retrieved using the KM by converting unavailable data into the zero constant. However, the theoretical reason behind such conversion has not been confirmed to date. In order to explain this theoretical reason, we convert unavailable measurement data into a constant and demonstrate that the imaging function of the KM can be expressed by an infinite series of the Bessel functions of integer order of the first kind, the object's material properties, and the converted constant. Following the theoretical result, we confirm that converting unknown data into the zero constant guarantees good results and unique determination of the objects. Finally, various numerical simulation results from Fresnel experimental dataset are presented and discussed to validate the theoretical result. [ABSTRACT FROM AUTHOR]

Feedback field-effect transistors (FBFETs) have been studied to obtain near-zero subthreshold swings at 300 K with a high on/off current ratio ~1010. However, their structural complexity, such as an epitaxy process after an etch process for a Si channel with a thickness of several nanometers, has limited broader research. We demonstrated a FBFET using in-plane WSe2 p−n homojunction. The WSe2 FBFET exhibited a minimum subthreshold swing of 153 mV/dec with 30 nm gate dielectric. Our modeling-based projection indicates that the swing of this device can be reduced to 14 mV/dec with 1 nm EOT. Also, the gain of the inverter using the WSe2 FBFET can be improved by up to 1.53 times compared to a silicon CMOS inverter, and power consumption can be reduced by up to 11.9%. [ABSTRACT FROM AUTHOR]

Here we revisit the electrostatics of material systems comprising of free charges and linear, homogeneous, and isotropic (LHI) dielectrics. We focus on D(r) suggesting that this is the primary vector field of electrostatics. We show that D(r) is sufficient to conceptually describe all underlying physics and to mathematically accomplish all necessary calculations, beforehand, independently of the secondary vector fields P(r) and E(r) that, if needed, can be easily calculated from D(r). To this effect, we introduce a P-D electric susceptibility, χε, with − 1 ≤ χ ε ≤ 0 , that couples linearly P(r) with D(r) (instead of the standard P-E electric susceptibility, χe, with 0 ≤ χ e < ∞ , that couples linearly P(r) with E(r)). This concept restores the somehow misleading causality/feedback between P(r) and E(r) of the standard formulation, captures efficiently the underlying physics, enables electrostatics to obtain a form analogous to that of magnetostatics, and facilitates analytical/computational calculations in relevant systems. To document these claims, we provide technical means, among others, the free scalar potential, U f r , and clarify the conditions that enable the calculation of D(r) on a standalone basis, directly from the free charge density, ρ f , and the electric susceptibility, χε, of the LHI dielectrics. Our concept sets interesting perspectives for the treatment of all dielectrics. [ABSTRACT FROM AUTHOR]

Digital microfluidic chips (DMCs) have shown the ability to flexibly manipulate droplets and particles, which is meaningful for biomedical applications in drug screening and clinical diagnostics. As a critical component of DMCs, the dielectric layer, with its key physical parameters (permittivity and thickness), directly determines the voltage distribution, thereby significantly affecting the manipulation performance. To optimize manipulation performance, simulation studies on dielectric layer parameters are essential during the DMC design. Existing simulation methods can evaluate the effect of dielectric layer parameters on droplet manipulation but encounter inherent challenges when analyzing the manipulation of particles within droplets. Here, we propose a versatile numerical analysis approach that can simultaneously analyze the effect of dielectric layer parameters on both droplet and particle manipulation, thereby optimizing the dielectric layer parameters to enhance the DMC manipulation performance. Initially, the voltage distributions corresponding to different sets of dielectric layer parameters are solved using electromagnetic field theory. Subsequently, the voltage distribution data are used to calculate the droplet and particle driving forces based on the principle of virtual work. Finally, by comparing the driving forces across different sets of dielectric layer parameters, the optimal dielectric layer parameters are determined to enhance the DMC manipulation performance. Experimental results demonstrate that the droplet and particle accelerations align with the simulated driving force trends, thereby validating our numerical analysis method. We anticipate that our method will be able to provide theoretical guidance for the optimization of dielectric layer parameters to obtain a desirable manipulation performance in more complex DMC designs. [ABSTRACT FROM AUTHOR]

Programmed droplet transport which is typically directed by surface energy gradients or external fields, is crucial in domains ranging from chemical reaction modulation to self‐powered intelligent sensing. However, droplet motion control remains constrained by path reconfiguration, requirements on chemical surface modification, and platform complexity. Here, a more universal plug‐and‐play droplet manipulation paradigm based on liquid‐solid contact electrification and triboelectricwetting on common dielectric surfaces is reported. By regulating the electrical double layer via asymmetric ion dynamics, the triboelectric charge polarity of droplets can be adjusted, enabling in situ manipulation without path reconfiguration dictated by the conventional droplet motion output. Droplets achieved an ultrahigh velocity of 450 mm s−1 on general surfaces, significantly exceeding the speeds observed in droplets subjected to constant electrostatic fields with chemical modifications. This flexible and modular functionally decoupled manipulation strategy offers an environmentally friendly, cost‐effective, and versatile paradigm, facilitating applications in chemical analysis and smart sensing. [ABSTRACT FROM AUTHOR]

Although light‐matter interaction and topology of photonic systems have been extensively studied, the topology induced novel light‐matter interaction phenomena in deep‐subwavelength region remain unexplored. Here, based on the non‐trivial topological singularity of 1D photonic crystals (PhCs), novel photonic spin Hall effects and abnormal beam behaviors are revealed in deep‐subwavelength region for the beams with nearly normal incidence, which beyond effective medium theory. The huge photonic spin Hall shift (PSHS) is observed around the singularity in the deep‐subwavelength region. The shape of reflected beam undergoes dramatic changes near the singularity, especially at the singularity, the reflected field is split as dipole‐like distribution for both polarizations. Physically, such a phenomenon is resulted from the destructive interference between the spin‐maintained beam and spin‐flipped beam. Based on these theoretical researches, super‐subwavelength thickness detecting, in which the wavelength is six orders of magnitude larger than the detecting scale, can be designed. Such sensitive detecting can also be applied to dielectric permittivity of PhC and background. Further more, by tuning the distance between two singularities in the deep‐subwavelength region, multi‐frequency channels sensitive detection and broadband platform with huge PSHS can be achieved. This system could be a platform to explore nontrivial light‐mater interaction in deep‐subwavelength region and to design of extremely sensitive detection devices. [ABSTRACT FROM AUTHOR]

Ferroelectric polymers with robust electrical polarization have been extensively investigated for capacitive energy storage. However, their inherent ferroelectric hysteresis loss limits the discharged energy density and compromises energy efficiency. Here, a heterogeneous nanolayered composite of ferroelectric polymer poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE)) and Al2O3 is presented, which effectively mitigates ferroelectric hysteresis loss while maintaining high polarization and enhanced breakdown strength. Phase‐field simulations indicate that the polarization behaviors of the heterogeneous layered structure are jointly influenced by the thickness and dielectric constant of each component, which balances the electrical energy and Landau energy within the heterogeneous system. Guided by the theoretical simulations, optimized polarization behaviors are achieved with a significant reduction in remnant polarization and ferroelectric loss in the P(VDF‐TrFE)/Al2O3 composites through careful control of P(VDF‐TrFE) thickness at nanometer scale. Moreover, the presence of multiple interfaces in the layered composites leads to a remarkable enhancement in polarization and breakdown strength. Consequently, an ultrahigh energy density of about 108 J cm−3 is achieved with a high charge–discharge efficiency of exceeding 80%. This work not only presents a straightforward approach to modify the polarization behaviors of ferroelectric polymers but also demonstrates a promising strategy for developing high‐energy‐density polymer nanocomposites. [ABSTRACT FROM AUTHOR]

The recent high demand of secondary electron emission yield (SEY) measurements in dielectric materials from space industry has driven SEY laboratories to improve their facilities and measurement techniques. SEY determination by the common capacitive method, also known as pulsed method, is well accepted and has given satisfactory results in most cases. Nevertheless, the samples under study must be prepared according to the experimental limitations of the technique, i.e. they should be manufactured separated from the devices representing faithfully the surface state of the own device and be as thin as possible. A method based on the Kelvin probe (KP) is proposed here to obtain the SEY characteristics of electrically floating Platinum, Kapton and Teflon placed over dielectric spacers with thicknesses ranging from 1.6 to 12.1 mm. The results are compared with those of the capacitive method and indicate that KP SEY curves are less sensitive to spacer thickness. An explanation based on the literature is also given. In all, we have established that KP is better suited for the analysis of dielectric samples thicker than 3 mm. [ABSTRACT FROM AUTHOR]

The electronic transport properties of the bilayer graphene double layer (BLGDL) system at T = 0 K using the Boltzmann transport equation are reported here. The conductivity of the BLGDL system has been calculated with varying parameters as relative carrier concentration (n (c) / n (C I)) , short-range (point defect) and long-range (Coulomb charge) impurity concentration, relative dielectric constant (ε r) and interlayer distance (d). The maximum conductivity has been achieved in the absence of short-range impurity. The short-range impurity plays a non-trivial meaningful role in high dielectric and high carrier concentration regimes and limits the conductivity. For higher ε r and higher n (c) / n (C I) values, the nature of the conductivity curve turns out to be of a sublinear nature, while in all other cases, it shows a superlinear trend. Suitable selection of relative dielectric constants, relative carrier concentration and interlayer distance helps to improve the conductivity of the BLGDL system. If the dielectric constant of the spacer is higher than the substrate material, the thickness of the spacer material helps remarkably in enhancing conductivity. Moreover, a comparison of BLGDL with our previously reported MLG–MLG double layer graphene system (DLGS) confirms that higher conductivity is achieved in the case of BLG–BLG system compared to DLGS. [ABSTRACT FROM AUTHOR]

The excellent complementary metal-oxide-semiconductor compatibility and rich physicochemical properties of hafnia-based materials, in particular the unique ferroelectricity that surpasses of conventional ferroelectrics, make hafnia-based devices promising candidates for industrial applications. This Perspective examines the fundamental properties of hafnia-based materials relevant to neuromorphic devices, including their dielectric, ferroelectric, antiferroelectric properties, and the associated ultra-high oxygen-ion conductivity. It also reviews neuromorphic devices developed leveraging these properties, such as resistive random-access memories, ferroelectric random-access memories, ferroelectric tunnel junctions, and (anti)ferroelectric field-effect transistors. We also discuss the potential of these devices for mimicking synaptic and neuronal functions and address the challenges and future research directions. Hafnia-based neuromorphic devices promise breakthrough performance improvements through material optimization, such as crystallization engineering and innovative device configuration designs, paving the way for advanced artificial intelligence systems. [ABSTRACT FROM AUTHOR]

Construction of built‐in electric field (BIEF) in nanohybrids has been demonstrated as an efficacious strategy to boost the dielectric loss by facilitating oriented transfer and transition of charges, thus optimizing the electromagnetic wave absorption property. However, the specific influence of BIEF on interface polarization needs to explore thoroughly and the BIEF strength should be further augmented. Herein, several dielectric systems incorporated Mott–Schottky heterojunctions and hollow structures are designed and constructed, where bimetallic zeolitic imidazolate framework are employed to derive Cu‐ZnO Mott–Schottky heterojunctions, and hierarchical structures and BIEF are further enriched by introducing hollow structure and reduced graphene oxide. The well‐established “double” BIEF verified by theoretical calculation and hollow engineering can regulate the conductivity, and enhance the polarization relaxation effectively. Especially, there always coexisted both enhanced charge separation and reversed charge distribution in this “double” BIEF, boosting the interface polarization. Attributing to the synergy of well‐matched impedance and amplified dielectric loss, the obtained hybrids exhibited superior absorption (reflection loss of −46.29 dB and an ultra‐wide effective absorption bandwidth of 7.6 GHz at only 1.6 mm). This work proves an innovative model for dissecting dielectric loss mechanisms and pioneers a novel strategy to explore advanced absorbers through enhancing BIEF. [ABSTRACT FROM AUTHOR]

Metasurfaces are established tools for manipulating light and enhancing light-matter interactions. However, the loss of conventional meta-atoms usually limits the performance potential of metasurfaces. In this study, we propose a class of metasurfaces based on discretized meta-atoms able to mitigate the radiative and intrinsic losses. By discretizing meta-atoms, we reduce the loss of metal metasurfaces to levels comparable to dielectric metasurfaces in the short-wavelength infrared region at the surface lattice resonance mode. Furthermore, we propose a coupling model to explain the observed reduction in loss in full agreement with the results obtained from finite-element method. We also reproduce this phenomenon using dielectric metasurface at electric and magnetic resonances in the visible region. Our finding offers valuable insights for the design and application of metasurfaces, while also providing theoretical implications for other resonance fields beyond metasurfaces. Metasurfaces are established tools for manipulating light and enhancing light-matter interactions, but the loss of conventional meta-atoms usually limits the performance potential of metasurfaces. Here, the authors propose a class of metasurfaces based on discretized meta-atoms able to mitigate the radiative and intrinsic losses, as interpreted by their built coupling model. [ABSTRACT FROM AUTHOR]

The Poisson–Boltzmann equation has been employed to consider the electrostatic interaction between two charged dielectric spherical particles in a solution of a symmetric electrolyte. The interaction forces between the particles of the same radius have been calculated by the finite element method under the condition of uniform charge distribution on their surfaces in the absence of an external field. The dependence of the electrostatic repulsion forces between the particles on the magnitude of the particle charges and the dielectric permittivities of the particle materials and the ambient medium has been analyzed. [ABSTRACT FROM AUTHOR]

The photonic spin Hall effect, characterized by its polarization-driven spin-related displacement, has played an essential role in coding information processing. In this Letter, using a two-period double-layer dielectric plate, the displacement changes within the angle region are first observed, and a two-bit effective coding is achieved through non-uniform quantization of displacement values and coding. Afterward, by constructing Brewster angles (BAs), effective three-bit coding is achieved at the selected BA by dividing the angle domain. By changing the relative refractive index of the constituent materials (nB), effective coding is achieved at corresponding angles (45°–85°). By connecting two-bit and three-bit coding, a five-bit coding is fulfilled. By setting the last six invalid values, effective correspondence of 26 English letters is obtained. At the same time, the largest displacement peak itself is huge and varies accordingly with different values of nB. This work can provide some reference for designing optical coders. [ABSTRACT FROM AUTHOR]

Vertical Metal–Insulator–Semiconductor (MIS) capacitors with an Al2O3 thin film as a gate insulator have been fabricated on homoepitaxial GaN-on-GaN samples. The effect of the annealing treatments on the MIS characteristics has been investigated exploring two different approaches: Post-insulator-Deposition-Annealing (PDA) and Post-gate-Metallization-Annealing (PMA), i.e., annealing on the bare Al2O3 layer and annealing after the gate metallization deposition on Al2O3. The direct comparison between PDA and PMA is crucial to understand the impact of the metal/dielectric interface quality on the behavior of the Al2O3/GaN MIS capacitors. The efficacy of annealing has been monitored as a function of metal gates having different work functions: nickel (Ni), molybdenum (Mo), and tantalum (Ta). It has been found that both PDA and PMA approaches are equally able to improve the Al2O3/GaN interface electrical quality. However, the PMA demonstrates an additional beneficial effect on the metal/Al2O3 interface. In particular, the possible chemical reactions activated by the annealing process at the metal/dielectric interface can perturb the known metal/dielectric dipole responsible for Fermi-level pinning phenomena, causing a positive shift of the flat voltage (VFB), which depends on the metal, and approaching the theoretical value in the case of Mo and Ta. [ABSTRACT FROM AUTHOR]

Frequency-domain dielectric spectroscopy (FDS) technology is commonly utilized for assessing the condition of power equipment with oil–paper insulation. Nonetheless, its application in practical field conditions is limited because of the constantly changing temperature in the measurement environment and the equipment under inspection. To address this issue, this paper presents a method for separating the conductance and polarization components in dielectric response, and conducts experiments to measure the dielectric curves of oil–paper samples at five different temperatures. Subsequently, the dielectric curves in the entire frequency range are decomposed into three distinct microscopic dielectric processes: low-frequency conductivity, low-frequency polarization, and high-frequency polarization. The impact of temperature variation on these microscopic dielectric processes is investigated to establish a connection between them and the physical meaning of the complex dielectric constant. This leads to proposing a new method for temperature translation normalization of dielectric curves. Experimental results reveal that each microscopic dielectric curve undergoes translation due to temperature changes, with varying amplitudes of translation. Based on the temperature translation characteristics of these microscopic processes, the suggested temperature translation normalization method for dielectric responses demonstrates excellent efficacy, aiding in the precise assessment of power equipment insulation status. [ABSTRACT FROM AUTHOR]

A folded transmitarray antenna (FTA) with low profile, high efficiency, and broadband is proposed. The transmission unit‐cell is composed of two metallic layers of bowknot‐shaped patches printed on a single layer of dielectric substrate. By regulating bowknot‐shaped patches' dimension and mirroring elements' top and bottom layers, 360° phase swing and high transmission magnitudes are obtained. With the introduction of a reflectarray integrated with a feed horn in the middle, an FTA is designed based on ray tracing principle, leading to a profile reduced to 1/3 of the focal distance of traditional transmitarrays. According to testing results, 15.5% 1 dB gain bandwidth, 30.9% 3 dB gain bandwidth, and 42.3% peak aperture efficiency are achieved. These outstanding performances demonstrate its good potential for a wide range of high‐gain applications. [ABSTRACT FROM AUTHOR]

In this study the dielectric properties are experimentally studied and also analyzed the influence of guest particles on the functional properties of various liquid crystals. The polar and elastic energy of the nanoparticles is found to affect the functional energy of pure suspension. In addition to this, the functional dielectric anisotropy of the dispersed system takes modified form. In this study experiments are performed on various materials to find dielectric anisotropy and also found in good agreement with theoretical explanation. [ABSTRACT FROM AUTHOR]

In this paper, a kind of metastructure–photonic crystal (MPC) with multi-frequency asymmetric absorption–transmission properties is proposed. It is composed of various dielectric layers arranged in a periodically tilting pattern. When electromagnetic waves (EMWs) enter from the opposite direction, MPC shows an obvious asymmetry. EMWs are absorbed at 13.71 GHz, 14.37 GHz, and 17.10 GHz in forward incidence, with maximum absorptions of 0.919, 0.917, and 0.956, respectively. In the case of backward incidence, transmission above 0.877 is achieved. Additionally, the MPC is utilized for refractive index (RI) sensing, allowing for wide RI range detection. The refractive index unit is denoted as RIU. The RI detection range is 1.4~3.0, with the corresponding absorption peak variation range being 17.054~17.194 GHz, and a sensitivity of 86 MHz/RIU. By adjusting the number of MPC cycles and tilt angle, the sensing performance and operating frequency band can be tailored to meet various operational requirements. This MPC-based RI sensor is simple to fabricate and has the potential to be used in the development of high-performance and compact sensing devices. [ABSTRACT FROM AUTHOR]

As a critical component of electrostatic capacitors, the polymer dielectric directly affects the performance of the capacitor. In this work, Polycarbonate (PC)/Polyvinylidene fluoride (PVDF) asymmetric bilayer polymer dielectrics were prepared, and the influence of different polymer materials' barrier characteristics on various electrical properties of composite dielectrics was studied by changing the direction of applied electric fields. Research has found that the dielectric constant of a composite dielectric is between PVDF and PC (approximately 4.8 at 10 Hz) and is independent of the relative position of PVDF and PC in the dielectric. However, the relative position of PC and PVDF has a significant impact on the energy-storage characteristics of composite dielectrics. When PVDF comes into contact with the negative electrode, even though PC has a higher hole barrier, the composite dielectric can only withstand a maximum electric-field strength of 400 MV/m, which is much lower than the maximum electric-field strength that pure PC can withstand (520 MV/m), and it only achieves an energy-storage density of 3.7 J/cm3. When the PC comes into contact with the negative electrode, the high electron barrier of the PC effectively suppresses the injection of electrons at the electrode. It can withstand the same electric-field strength as PC (520 MV/m), achieving an energy-storage density of 5.48 J/cm3, which is 1.46 times that of pure PC and 1.64 times that of PVDF. This experiment effectively combined the advantages of PC and PVDF by utilizing the electron/hole barrier of polymer materials to obtain a fully organic dielectric with excellent energy-storage performance. [ABSTRACT FROM AUTHOR]

In recent years, the emergence of metasurfaces has brought revolutionary changes to the generation and processing of vortex beams, triggering widespread research interest. Meanwhile, the longitudinally varying features of propagating beams provide new design freedom for realizing multi‐dimensional optical manipulation and promote the advancements of related areas such as microscopic detection, microfabrication, and biomedical applications. In addition, self‐accelerating Bessel beams are promising for a wide range of applications such as particle manipulation and medicine due to their nondiffracting, self‐healing as well as obstacle avoidance properties. In this paper, a novel kind of curved transmitted high‐order Bessel beams with longitudinally varying features based on form‐birefringent metasurface, by simultaneously manipulating the phase profiles of output orthogonal polarization components is demonstrated. Multiple dimensions of the beam, including the propagation trajectory, polarization state, and orbital angular momentum, can be tailored arbitrarily. For verifying the feasibility of the demonstrated method, two samples with different propagation trajectories, as well as different variations of orbital angular momentum, are designed and experimentally demonstrated. Such a novel approach can open new doors for the manipulation of vortex beams and can be used for depth sensing and distance measurement in complex environments. [ABSTRACT FROM AUTHOR]

Elastomeric polymer materials are of interest due to their stretchability, low‐temperature processing, and scalability. In addition, the incorporation of 2D materials can further enhance the dielectric properties and capacitance of elastic polymer materials, thereby reducing the driving voltage and energy consumption. In this study, titanium dioxide (TiO2) nanosheets are cross‐linked with nitrile butadiene rubber using thiol‐ene click chemistry, which leads to the preparation of nanocomposite dielectric films with stretchability and high dielectric constant. Furthermore, by controlling the doping amount of the nanosheets, it is observed that the capacitance of the nanocomposite films increases from 25.61 to 684.67 nF cm−2, and the dielectric constant increases from 14.96 to 161.98. Finally, the stretchable nanocomposite films exhibit good insulating properties even at 50% strain. In this study, insight is provided into the potential of in situ cross‐linking between elastic polymer materials and 2D materials to produce high‐k dielectric materials with both stretchability and high insulating properties. [ABSTRACT FROM AUTHOR]

Intense field dielectrics (IFD) are widely used in the air purification industry. DC power supplies must be designed to provide a high voltage for IFD products. Therefore, this paper introduces a compact 10 kV high-voltage DC power supply tailored for IFD air purification. It employees a novel controller, which is a fusion of a fixed-frequency PWM-based sliding-mode controller and a phase-shift full-bridge configuration. The superiority of the proposed DC power supply topology is demonstrated. Rigorous simulation analysis employing MATLAB/Simulink shows that the robustness and stability of the new controller are much better than fixed-frequency PWM-based sliding-mode controllers. Subsequently, a high-voltage DC power prototype is fabricated, followed by comprehensive experimental validation. Test results underscore the stability of the DC power supply under normal operating conditions. Notably, when the controller adopts a linear PI configuration, the DC voltage output ripple is contained within a stringent threshold of ≤ 0.4%. Moreover, in the presence of AC power system oscillations, the novel controller showcases its ability to achieve a heightened response speed, which contributes to the robustness of the DC power supply. [ABSTRACT FROM AUTHOR]

As an alternative disinfection technology, air plasma is limited to achieve wider application due to its restricted disinfection level and hazardous by‐products including O3 and NOx. In this work, a time‐sharing synergy strategy is proposed, where NO and NO2 are first generated by a dielectric barrier discharge reactor in NOx mode, and then the discharge is switched into O3 mode by increasing flowrate, thus producing large amounts of high‐valence NOx for efficient disinfection in sealed space. The disinfection effect of time‐sharing synergy is about 2 logs higher than using single O3 or NOx mode with the same discharge power. The concentration of high‐valence NOx is highly correlated with disinfection effect. Finally, all disinfection ingredients are removed after 2‐min gas‐washing and heating. [ABSTRACT FROM AUTHOR]

The 0.29PSN-0.36PMN-0.35PT: x mol Nd2O3 (x = 0, 0.01, 0.015, 0.02, 0.025, and 0.03) piezoelectric ceramics are fabricated manufactured through the high-temperature sintering. Nd3+ doping significantly enhanced the piezoelectric and dielectric properties of PSN-PMN-PT, with the ceramic containing 0.025 mol Nd3+ exhibiting the optimal performance: d33 = 890 pC N−1, ɛr = 5735, d33* = 1094 pm V−1, Ec = 4.32 kV cm−1, Tm = 136 °C, and Pr = 4.32 µC cm−2. Phase structure analysis and Rayleigh analysis results show that the excellent dielectric and piezoelectric responses of the ceramic are mainly due to the synergistic effect of MPB and the significant improvement of nano-scale local structural heterogeneity. Moreover, the variation rate of d33 remained as low as 5% in the temperature range from room temperature to 120 °C. These comprehensive findings demonstrate that PSN-PMN-PT: 0.025 mol Nd2O3 ceramics excel in both their piezoelectric capabilities and thermal stability, thus rendering it an attractive material for high sensitivity sensor. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) for mechanical energy harvesting has been regarded as one of the most prospective energy technologies for the new era. However, inevitable material wear during triboelectrification results in output reduction and even failure of the TENG. In this work, a submillimeter‐scale superlubric TENG (SS‐TENG) is reported that enables ultra‐low friction coefficient (µ) and stable power generation. By using the micro/nano‐processing technology, the interdigital electrodes are embedded into the dielectric layer as a flat surface, on which the highly‐hydrogenated diamond‐like carbon (PLC) is deposited as the triboelectric layer to effectively reduce the friction coefficient. The frictional properties are systematically investigated at different parameters, in which a submillimeter‐scale (130 µm) superlubricity state (µ = 0.0084) is achieved at 4 N, 2 Hz and nitrogen atmosphere. Meanwhile, the SS‐TENG has a maximum power density of 3 mW m−2, which can remain stable at the superlubric condition. This work has first realized the freestanding‐mode superlubric TENG in submillimeter scale and provided a viable strategy for the development of long‐lifetime TENG, which may have great applications in frictional energy recovery from mechanical components, human joint motion, and the natural environment. [ABSTRACT FROM AUTHOR]

Stretchable dielectric polymer with high dielectric constant is a major component for electroluminescent devices. However, the intrinsic instability toward water severely limits their further applications in marine environment. Here, a transparent, underwater stable, and self‐healable dielectric material with high dielectric constant is reported. The electroluminescent device based on this newly designed fluoropolymer can work stably in aqueous conditions. There is no significant attenuation of mechanical and optoelectronic property after immersed in water and salty water for a month. The intrinsic self‐healing ability of the device makes it robust and resilient against unexpected minor or severe damages. [ABSTRACT FROM AUTHOR]

A cost-effective planar microstrip-based dielectric sensor with four fluidic channels on its ground plane is proposed for estimating the concentration and complex dielectric constants of ethanol/water mixtures. The channels are placed on the long sides of the slot resonators, which are slightly carved from the substrate. The sensor prototype is fabricated, showing good agreement between simulated and measured parameters. The sensor's resonance characteristics, influenced by the binary mixtures, are used to estimate the dielectric constants with an empirical relation. Validation is achieved through good correspondence with literature values. The sensor's resonance can be tailored by adjusting the number of fluidic channels. With a normalized sensitivity of 0.063% using 17.28 µl of material-under-test, the sensor is label-free, reusable, non-destructive, contactless, and suitable for lab-on-chip chemical sensing applications. [ABSTRACT FROM AUTHOR]

Droplet-based electricity generators (DEGs) have garnered significant interest due to their straightforward metal substrate/dielectric/metal electrode configurations and their capacity to produce instantaneous high power. This study investigates the influence of droplet conductivity and drop conditions on circuit parameters through an analysis of I–V characteristics under varying load resistance conditions. The results reveal that alterations in droplet resistance and polytetrafluoroethylene (PTFE) charge density due to varying droplet dynamics play a pivotal role in shaping DEG output. The charged state of PTFE on DEG was found to differ with the expansion and contraction of the droplets. [ABSTRACT FROM AUTHOR]

Recently, microwave dielectric ceramics with an oxyfluoride cubic rock salt structure have been widely studied due to their excellent microwave dielectric properties. However, the sintering mechanism of this material, especially the role of F-ions, is not clear. Here, the ceramic samples with two different LiF addition strategies were prepared by a conventional solid-phase reaction method. The sintering mechanisms of both samples were discussed in detail by analyzing the sintering activation energy, F-ions distribution, and concentration of oxygen vacancies by linear shrinkage, SEM-EDS, and XPS. The best microwave dielectric properties were obtained for Li 2 MgTiO 4 +4 wt% LiF (LiF-B) ceramics sintered at 950°C: ε r = 18.0, Q×f = 82,100 GHz, and τ ƒ = −32.7 ppm/°C. [ABSTRACT FROM AUTHOR]

Focusing on the high resistivity together with low intrinsic conduction in BaTiO 3 –BiMeO 3 materials, it can contribute to the development of reliable high-temperature capacitor materials. In this work, x (Bi 0·5 Li 0.5)TiO 3 -(0.8- x)BaTiO 3 -0.2BiScO 3 (where x ranges from 0 to 0.2) ceramics were fabricated by a solid reaction method. The temperature stability of dielectric permittivity and resistance are improved significantly by the introduce of (Bi 0·5 Li 0.5)TiO 3 (referred to as BL) compared to BaTiO 3 –BiMeO 3. The composition discrepancy due to chemical inhomogeneity can be determined by SEM and EDS mapping although XRD exhibit a single perovskite phase. The characteristics of distinct conductivity behaviors in micro-regions was measured by kelvin probe force microscopy (KPFM). The non-stoichiometry gives rise to two kinds of defects for charge compensation: an ionic compensation and oxygen-vacancy compensation in different grains. The increase of the hopping activation energy of charged carries enhances the high-temperature resistance of the system. The sample of x = 0.15 shows very good temperature stability of dielectric permittivity in the temperature range from 200 °C to 400 °C, and that of x = 0.1 exhibits the highest resistivity of 3.6 MΩ cm at 570 °C. The proposed method gives an efficient strategy for improving the dielectric temperature stability and insulation by the special defect compensation in the perovskite oxides. [ABSTRACT FROM AUTHOR]

Detoxification is one of the most important liver functions. Therefore, liver is the front line of defense when the biosystem faces drug overdose, toxins, and anything that may cause harm. Some famous antibiotics are known for their side effects on liver; one of them is amoxicillin, AM. This work has investigated the toxic effect of amoxicillin on rat's liver with overdose (90 mg/kg) and has studied the ameliorative role of protective and therapeutic Ashwagandha seeds extract (ASE) at doses (100, 200, and 300 mg/kg) against this toxicity. To achieve this work, the authors used two modalities; the first is liver histopathology to figure out the amoxicillin and ASE effects and to detect the sensitivity of another modality; the electric modulus, and its related thermodynamic parameters of liver tissue. Histopathological examination showed that the role of therapeutic ASE in reducing amoxicillin (AM) toxicity was more effective than the protective one. Also, most dielectric and thermodynamic results achieved the same result. Histopathology confirmed the liver injury by amoxicillin and the partial repair by the biosystem using ASE. Moreover, electric modulus, related dielectric parameters, and their thermodynamic state functions showed different changes in their values under the effect of amoxicillin. Using ASE helped the biosystem to restore these changes near their control values. [ABSTRACT FROM AUTHOR]

Metasurfaces are opening promising flexibilities to reshape the wavefront of electromagnetic waves. Notable optical phenomena are observed with the tailored surface plasmon, which is excited by metallic components in the visible spectrum. However, metamaterial or metasurface devices utilizing metallic materials encounter the challenge of low transmission efficiency, particularly within the visible spectrum. This study proposes a multilayer design strategy to enhance their transmission efficiency. By incorporating additional metal layers for improvements in the transmission efficiency and dielectric layers as spacers, cavities are formed along the propagation direction, enabling the modulation of transmittance and reflection through a process mimicking destructive interference. An analytical model simplified with the assumption of deep-subwavelength-thick metal layers is proposed to predict the structural parameters with optimized transmittance. Numerical studies employing the rigorous coupled wave analysis method confirmed that the additional metal layers significantly improve the transmittance. The introduction of the extra metal and dielectric layers enhances the transmission efficiency in specific spectral regions, maintaining a controllable passband and transmittance. The results indicate that the precise control over the layers' thicknesses facilitates the modulation of peak-to-valley ratios and the creation of comb-like filters, which can be further refined through controlled random variation in the thickness. Furthermore, when the thickness of the silver layer followed an arithmetic sequence, a multilayer structure with a transmittance of approximately 80% covering the entire visible spectrum could be achieved. Significantly, the polarization extinction ratio and the phase delay of the incident beams could still be modulated by adjusting the geometrical structure and parameters of the multilayer metamaterial for diversified functionalities. [ABSTRACT FROM AUTHOR]

This paper presents the transmission characteristics of flexible solid circular dielectric waveguides in the terahertz frequency band. In this paper, we measured the electrical properties of certain polymers within 325–500 GHz. Through simulation and measurement, the transmission loss, bending loss, and electric field distribution of solid-core polymer dielectric waveguides were analyzed and discussed. Additionally, we considered the surrounding cladding of the dielectric waveguide, the signal-feeding mode transmitter, and the interconnection of the dielectric waveguide. Ultimately, in the operating frequency range of 325–500 GHz, we selected PTFE rods with diameters of 0.5 mm and 1 mm as the dielectric waveguides, with measured transmission loss of less than 30 dB/m and 33 dB/m, respectively, and bending loss of less than 1 dB/m. The described dielectric waveguide has engineering significance for short-distance connections in complex geometric environments and provides a reference for subsequent research. [ABSTRACT FROM AUTHOR]

Metasurfaces can replace bulk optical components in a more compact form factor in applications including communication systems, sensors, and manufacturing technology. However, their design and fabrication is challenging due to competing demands of selecting meta-atoms that simultaneously provide the required amplitude and phase modulation while being robust to fabrication errors. Here, we develop two design heuristics to assist with the down-selection of meta-atoms into sensitivity-informed libraries, based on either selecting meta-atoms with minimal sensitivity or minimizing the relative sensitivities between meta-atoms. We evaluate both methods on a polarization-dependent phase mask and compare the resulting phase and intensity errors. [ABSTRACT FROM AUTHOR]

The development of metal–insulator–semiconductor (MIS) capacitors requires device miniaturization and excellent electrical properties. Traditional SiO2 gate dielectrics have reached their physical limits. In this context, high-k materials such as TiO2 are emerging as promising alternatives to SiO2. However, the deposition of dielectric layers in MIS capacitors typically requires high-vacuum equipment and challenging processing conditions. Therefore, in this study, we present a new method to effectively fabricate a poly(vinylidene fluoride) (PVDF)-based TiO2 dielectric layer via electrospinning. Nano-microscale layers were formed via electrospinning by applying a high voltage to a polymer solution, and electrical properties were analyzed as a function of the TiO2 crystalline phase and residual amount of PVDF at different annealing temperatures. Improved electrical properties were observed with increasing TiO2 anatase content, and the residual amount of PVDF decreased with increasing annealing temperature. The sample annealed at 600 °C showed a lower leakage current than those annealed at 300 and 450 °C, with a leakage current density of 7.5 × 10−13 A/cm2 when Vg = 0 V. Thus, electrospinning-based coating is a cost-effective method to fabricate dielectric thin films. Further studies will show that it is flexible and dielectric tunable, thus contributing to improve the performance of next-generation electronic devices. [ABSTRACT FROM AUTHOR]