To investigate the role of crystal anisotropy on the elastic–plastic deformation of BCC single crystals at high shock stresses, molybdenum (Mo) single crystals were shock compressed along the [100], [111], and [110] orientations at elastic impact stresses between 20 and 110 GPa. Laser interferometry was used to measure shock wave velocities and particle velocity histories. Along the [100] and [111]

We have overcome two drawbacks involved in series-connected double-junction (S-2J) and triple-junction (S-3J) photovoltaic cells to compose monolithic modules of artificial photosynthesis consisting of directly connected photovoltaic cells and electrolyzers of the same size. One is current mismatching among the subcells under solar spectrum variation. The other is inefficient utilization of high-energy

Dislocations are major structural defects in semiconductor materials, and they have negative impacts on the performance and reliability of electronic devices. The Burgers vector ( b → ) of a dislocation is one of the most important characteristics that determines its behavior in an operating device. In this study, we used synchrotron x-ray topography (XRT) to perform systematic observations of dislocations

The Z-pinch configuration offers the promise of a compact fusion device owing to its simple geometry, unity beta, and absence of external magnetic field coils. Increasing the axial current compresses the plasma, resulting in a rapid rise of the fusion reaction rate. Historically, the Z pinch has been plagued by fast growing instabilities that limit plasma lifetimes. Recent progress has resulted from

Dark current characteristics of germanium (Ge) vertical p-i-n photodetectors were studied. Ge photodetectors were demonstrated on the germanium-on-insulator (GOI) platforms realized via direct wafer bonding and layer transfer. GOI platforms with two different threading dislocation densities (TDDs) of 3.2 × 106 cm−2 (low TDD) and 5.2 × 108 cm−2 (high TDD) were varied via furnace annealing in oxygen

We report the design, fabrication, and characterization of a porous silicon-based omnidirectional mirror for the near infrared range. The structure consists of 300 porous silicon chirped dielectric layers, optimized to have omnidirectional reflectivity response from 1000 to 2000 nm wavelength range. Measurements of reflectivity spectra are presented for non-polarized light at several incident angles

Although silicon substrate temperature is known to be important in many plasma processes, measuring it involves various difficulties due to the complexity of plasmas. In previous work, the authors proposed an optical-interference contactless thermometer (OICT) for interferometric temperature measurements with high temporal resolution and the ability to measure a substrate surface from behind. In the

Bipolar high power impulse magnetron sputtering (HiPIMS) with a yttrium target is investigated with the help of time-resolved diagnostics. The bipolar HiPIMS discharge is operated with a negative pulse with a width of 100 μ s, which is immediately followed by a positive pulse (pulse voltage up to +60 V) with a duration of ∼ 310 μ s. The time-resolved floating potential first rises to a large positive

A physically unclonable function (PUF) is an embedded hardware security measure that provides protection against counterfeiting. Here, we present our work on using an array of randomly magnetized micrometer-sized ferromagnetic bars (micromagnets) as a PUF. We employ a 4 μ m thick surface layer of nitrogen-vacancy (NV) centers in diamond to image the magnetic field from each micromagnet in the array

The discovery of single-phase multiferroic materials and the understanding of intriguing physics of the coupling mechanisms between their spin and polarization are important for the next generation of multifunctional devices. In this work, we report dielectric, ferroelectric, and magnetization results of Pd-substituted room-temperature magnetoelectric multiferroic Pb(Zr0.20Ti0.80)0.7Pd0.3O3 (PZTPd)

This paper reveals the existence of a critical separation distance ( d c) beyond which the elastic interactions between a pair of monovacancies in graphene or hexagonal boron nitride become inconsequential for the strength and toughness of the defective lattice. This distance is independent of the chirality of the lattice. For any inter-defect distance higher than d c, the lattice behaves mechanically

We model the highly reduced thermal conductivity of nanostructured materials observed in nanoribbons. For highly scaled structures, such as wires with diameters on the order of 20 nm, physical effects beyond classical boundary scattering, including acoustic softening, become important. To date, work on acoustic softening has focused on reductions in group velocity. However, a reduction in the group

Caloric materials respond to external field variations such as magnetic, stress, and electric. A simple caloric cycle uses entropy and temperature changes resulting from a single field variation to provide useful transfers of work and heat. An active regenerator cycle increases operating range and efficiency of a caloric material when property variations are appropriately matched to design conditions

Mechanical metamaterials can be used to control elastic waves, but it is challenging to obtain multiple or ultrawide bandgaps. A one-dimensional simple periodic system with multi-resonator unit cells can achieve multiple locally resonant bandgaps. A unit cell that comprises multiple cells is called a hybrid unit cell. Two different metamaterials with hybrid unit cells are proposed to achieve a wider

Microwaves are a form of non-ionizing radiation composed of electric (E) and magnetic (H) fields and are absorbed by biological tissues with a high water content. Our study investigated the effect of the E field, H field, and a combination of both (E + H) field’s exposure of structurally diverse micro-organisms, at a frequency of 2.45 GHz. We observed that the exposure to a microwave E field of an

Two-dimensional (2D) materials exhibit enhanced thermoelectric (TE) performance compared to bulk materials, which relies heavily on lattice thermal conductivity. Penta-X2C (X = P, As, and Sb) is a newly predicted 2D material family with promising potential applications in photocatalytic water splitting and photovoltaic and optoelectronic devices. To achieve a combination of photovoltaic and TE technologies

Mg2Si has attracted considerable attention as an environmentally friendly thermoelectric material. Previous studies have revealed that the thermoelectric performance of Mg2Si is strongly affected by tensile strain. The present study aims at determining the origin of the structural effect on the thermoelectric properties from the perspective of the effective mass, which allows the quantitative analysis

Synthetic powder, ore samples, and mineral single crystals of goethite ( α-FeOOH) were investigated with polarized Raman spectroscopy at temperatures from 293 K to 473 K. The symmetry of the vibrational modes, observed in different scattering configurations, was determined unequivocally. The assignment of the Raman-active modes to definite atomic vibrations is supported by two types of lattice-dynamical

Thermal conductivity κ ( T ) of single crystal aluminum nitride grown by physical vapor transport has been measured at temperatures T from 5 to 410 K. The samples exhibit high thermal conductivity with a value of up to 316 W m − 1 K − 1 at room temperature and about 2800 W m − 1 K − 1 at a peak of 66 K. At lowest temperatures, κ ( T ) approaches the conductivity limited by the diffuse phonon scattering

The modulation of Schottky barrier height (SBH) due to defect migration has been suggested to be an important driving mechanism for resistive switching in metal–oxide–metal structures. Here, we explore the SBH and its modulation due to different interface structures and defects in the Pt|MgO|Pt(001) system using hybrid Heyd–Scuseria–Ernzerhof density functional theory. The computed magnitudes of SBH

Correct identification of local configurations of dopants and point defects in random alloys poses a challenge to both computational modeling and experimental characterization methods. In this paper, we propose and implement a computationally efficient approach to address this problem. Combining special quasirandom structures, virtual crystal approximation, and real-space lattice static Green’s functions

In contrast to relatively pure silica glass (fused silica—FS), commercial silica-rich glasses contain significant fractions of additional oxide components. In particular, soda-lime glass (SLG) consists of approximately 71% SiO2 by weight, which raises the question: what is the effect of additional cations on the shock compression response of silica-rich glasses? To address this question, plate impact

Multiple particle tracking microrheology (MPT) is a passive microrheological technique that measures the Brownian motion of probe particles embedded in a sample to characterize material rheological properties. MPT is a powerful tool that quantifies material rheology in the low moduli range while requiring only small sample volumes and relatively simple data acquisition using video microscopy. MPT quantitatively

Computational metamaterials have enabled the realization of real-time mathematical operations in spatial and time domains. Here, we present the design and experimental demonstration of time-domain differential operations based on an elastic wave computational metamaterial. For generality and universality, the linearity and the product rule for the wave-based differentiation are also verified, as well

We investigated the influence of oxygen vacancies on the magnetic and transport properties of ferrimagnetic NiCo2O4 (NCO) epitaxial films. Oxygen vacancies were introduced by annealing under reducing atmospheres NCO films whose cation composition was close to the stoichiometric one. We find that annealing NCO films under the vacuum reduces their magnetizations and increases their electrical resistivities

Structural rejuvenation in metallic glasses (MGs) induced by cryogenic thermal cycling has been intensively studied. However, the effect of thermal cycling on the atomic dynamics in MGs is still missing. In this work, we present a systematic study on the atomic dynamics in a La-based MG affected by sub-Tg annealing and thermal cycling. We find that the thermal cycling has little effect on the atomic

The density of nanofluids is an important thermophysical property whose value is required to evaluate various heat-transfer parameters such as the Reynolds number, the Nusselt number, pressure loss, and the Darcy friction factor. The determination of these parameters is central to the design of many heat-transfer applications. Notably, the density of nanofluids has received relatively little research

Crystallization processes of amorphous germanium–tin (GeSn) under low-energy electron-beam irradiation were examined using transmission electron microscopy (TEM). Freestanding amorphous GeSn thin films were irradiated with a 100 keV electron beam at room temperature. The amorphous GeSn was athermally crystallized by electron-beam irradiation, when the electron flux exceeded the critical value. Heterogeneous

Alternative n-type buffer layer such as In 2 S 3 has been proposed as a Cd-free alternative in kesterite Cu 2 ZnSn ( S , Se ) 4 (CZTSSe) solar cells. In this study, optical and electronic characterization techniques together with device analysis and simulation were used to assess nanoparticle-based CZTSSe absorbers and solar cells with CdS and In 2 S 3 buffers. Photoluminescence spectroscopy indicated

In this work, we present numerical calculations of the acoustic scattering properties of inclusions characterized by fractional order behavior. Fundamental quantities, such as the differential and the total scattering cross sections, are calculated for a wide range of forcing frequencies, and their characteristics are analyzed in the perspective of remote sensing and material characterization applications

A four-hole tellurite microstructured optical fiber (MOF) was designed and fabricated based on TeO2–Bi2O3–ZnO–Na2O (TBZN), and the fiber loss was 0.1 dB/[email protected] nm. Based on a 3 m tellurite MOF, dispersive wave (DW) generation and evolution was experimentally investigated at the pump wavelengths of 1778 nm, 1812 nm, and 1878 nm. With the increase of the average pump power, DWs trapped by

We investigate the impact of the dipole-active modes formed via the mode-mixing of the dipole mode with higher-order surface plasmon modes of a nanoegg on the radiative decay rate and quantum yield of an excited molecule near the nanoegg. The Purcell factor, rate of power dissipation by the emitter, and antenna efficiency of the nanoegg, as well as quantum yield enhancement of the emitter, were studied

A Talbot–Lau x-ray deflectometer can map electron density gradients in high energy density plasmas, as well as provide information about plasma elemental composition through single-image x-ray refraction and attenuation measurements. A new adaptation to a pulsed power environment used backlighting from copper X-pinches, allowing for electron density mapping of a low-Z object. Even though the X-pinch

Transition metal oxide thin films and heterostructures are promising platforms to achieve full control of the antiferromagnetic (AFM) domain structure in patterned features as needed for AFM spintronic devices. In this work, soft x-ray photoemission electron microscopy was utilized to image AFM domains in micromagnets patterned into La0.7Sr0.3FeO3 (LSFO) thin films and La0.7Sr0.3MnO3 (LSMO)/LSFO superlattices

Strong coupling between magnons and cavity photons was studied extensively for quantum electrodynamics in the past few years. Recently, the strong magnon–magnon coupling between adjacent layers in magnetic multilayers has been reported. However, the strongly coupled magnons confined in a single nanomagnet remains to be revealed. Here, we report the interaction between different magnon modes in a single

Morphotropic phase boundary (MPB) composition 0.94Na0.5Bi0.5TiO3–0.06BaTiO3 (NBT–6BT) has received industrial acceptance in certain aspects such as ultrasonic cleaners to replace those of lead-based systems. While detailed structure–property analysis on NBT–6BT is mostly confined to room temperature and above, less attention is paid with regard to their structure and property understanding below room

Accurate determination of three types of losses (dielectric, elastic, and piezoelectric) in piezoelectric materials is critical, since they are closely related to the performance of high-power piezoelectric devices. The standard k 33 mode has a number of serious deficits that hinder researchers from determining accurate physical parameters and losses. In order to overcome such deficits, “partial electrode”

Propylammonium lead iodide (C3H7NH3PbI3), a promising hybrid perovskite, is successfully synthesized by a solgel technique. Structural, optical, and dielectric properties have been studied in detail. The dielectric constant, loss factor, electric modulus, and AC and DC conductivity of this hybrid perovskite exhibit strong temperature dependence over the frequency range of 10 Hz ≤ f ≤ 8 MHz. The Nyquist

In this paper, we present an approach of measuring the SET kinetics of redox-based resistive memories at timescales below 100 ps. Automatic measurements with an RF pulse generator and a source measure unit allow the consecutive application of short electrical pulses and the precise detection of the device resistance. In addition, a statistical evaluation of the SET kinetics has been performed. By increasing

Optical absorption in amorphous tungsten oxide ( a WO 3), for photon energies below that of the bandgap, can be rationalized in terms of electronic transitions between localized states. For the study of this phenomenon, we employed the differential coloration efficiency concept, defined as the derivative of the optical density with respect to the inserted charge. We also made use of its extension to

Great improvements for wireless techniques and electronic devices require effective electromagnetic (EM) absorbing materials to solve EM radiation and interference problems. Herein, cobalt sulfide/reduced graphene oxide (CoS/rGO) nanocomposites were prepared through a simple one-pot hydrothermal method. The microwave absorption performance of CoS/rGO nanocomposites with different rGO proportions was

Self-suspended polyimide (PI) composite films were fabricated. Their diameter and thickness were 2.5 in. and 260 nm, respectively. A high ratio of diameter to thickness of 2.4 × 105 was obtained. The multiwalled carbon nanotubes (MWCNTs) were filled into PI to improve the optical absorption and the photothermal response. By using the N-methyl pyrrolidone solvent for both MWCNTs and poly(amic acid)

We report on the growth of AlN epilayers at reasonably low temperatures of 1050–1110 °C on non-miscut c-plane sapphire by metal organic chemical vapor deposition (MOCVD). A systematic study of growth parameters revealed that the thickness of the low temperature (LT) nucleation layer (NL) plays a critical role in improving the screw and edge dislocation densities and surface morphology of the AlN epilayer

The density of polarity-induced oxygen vacancies ( V O s) at the LaAlO 3 (LAO) surface of LAO / SrTiO 3 (STO) (001) heterostructures (HSs) and the density of induced carriers at the interface are quantitatively investigated. Using chemical equilibrium conditions combined with density-functional-theory calculations of total energy, we set up a model for the densities of the V O s and the carriers, which

We present vanadium dioxide (VO2) thin films having high resistivity contrast with silicon substrates through use of crystallized alumina (Al2O3) buffer layers, engineered for this purpose. We first optimized the process by depositing VO2 onto C-plane sapphire substrates prior to alumina thin films. The latter of which were grown via atomic layer deposition on silicon substrates. We then applied rapid

Carbon doping is used to obtain semi-insulating GaN crystals. If the carbon doping concentration exceeds 5 × 1017 cm−3, the carbon atoms increasingly form triatomic clusters. The tri-carbon defect structure is unambiguously proven by the isotope effect on the defects' local vibrational modes (LVMs) originally found in samples containing carbon of natural isotopic composition (∼99% 12C, ∼1% 13C) at

High-efficiency III-nitride deep-ultraviolet (DUV) lasers and light-emitting diodes (LEDs) with emission wavelengths of 240–260 nm are extremely difficult to realize due to large defect density from III-nitride materials and existence of optical polarization crossover from conventional AlGaN-based quantum wells (QWs). Free-standing wurtzite AlGaN templates have been studied and developed recently;

The electric field in a silicon p–n junction has been measured using pixelated scanning transmission electron microscopy. By using a convergence angle of 3.2 mrad, a spatial resolution better than 1 nm can be achieved leading to a rigid shift of the transmitted beam as it passes through an electric field. By precessing the beam around the optical axis at an angle of 0.1°, the effects of dynamical diffraction

Recent advances in optical microscopy instrumentation and processing techniques have led to imaging that both breaks the diffraction barrier and enables sub-pixel resolution. This enhanced resolution has expanded the capabilities of particle tracking to nanoscale processes in soft matter including biomolecular, colloidal, and polymeric materials. This tutorial provides a basic understanding of particle

In the design of maglev systems, the levitation force determines the levitation height and the dynamic stability associated with potential vibrations, especially the offset of the levitation point relative to the working point. However, such two key parameters are often antagonistic: a relatively low dynamic stability comes with a high levitation force, whereas a relatively low levitation force can

We present work on a novel In0.53Ga0.47As/AlAs metamorphic asymmetric spacer layer tunnel (mASPAT) diode structure, which was grown on GaAs by solid source molecular beam epitaxy. mASPAT diodes with different mesa sizes were fabricated and tested following growth under optimal conditions. The measured I–V characteristics of these tunneling devices showed rectifying behavior resulting from the asymmetric

High-performance electromagnetic wave absorption materials constitute key components of microelectronic devices. Traditional absorbents possess magnetic losses and/or dielectric losses, while the experimental approach for their simultaneous enhancement is still lacking. Here, we demonstrate that the core/shell structural [email protected] nanocapsules, functionalized by atomic-scale oxygen substitutions

We present a theoretical study of the nonlinear optical properties of shallow-donor impurities in semiconductors subjected to magnetic fields, hydrostatic pressures, and intense laser illumination within the Voigt configuration. The donor energy levels and their wave functions are obtained using a combination of nonperturbative and variational methods where intense laser field effects are exactly taken

The solid acid compound CsH2PO4 (CDP) is a superprotonic conductor for intermediate temperature range fuel cell applications. Doping CDP with rubidium can alter its transition temperature from normal phase to superprotonic phase. Powder samples of Cs1 − xRbxH2PO4 (0 ≤ x ≤ 1) were synthesized with 10 at. % intervals of x and analyzed at room temperature. A powder x-ray diffraction study showed three

Magnetic properties of highly magnetostrictive amorphous glass-coated microwires are strongly correlated to the presence of a glass coating that introduces a spatially inhomogeneous stress field distribution. We investigate the influence of mechanical stresses on the inclination of magnetic domain walls in magnetic microwires. Magneto-optical Kerr effect imaging is used to compare the tilted orientation

The recently discovered electrical-induced switching of antiferromagnetic (AF) materials that have spatial inversion asymmetry has enriched the field of spintronics immensely and opened the door for the concept of antiferromagnetic memory devices. CuMnAs is one promising AF material that exhibits such electrical switching ability and has been studied to switch using electrical pulses of length millisecond

The topologically protected vortex–antivortex (V–AV) domain structure in ferroelectric hexagonal manganites has been highly concerned recently, but its stability against intrinsic defects remains to be understood, given the claim that a topological structure would be robust against defects and other perturbations. In fact, it is also known that the V–AV structure is sensitive to the sample quality

We study the interaction between mechanical fields and the motion of charge carriers in a composite beam of flexoelectric (nonpiezoelectric) and semiconductor layers. The macroscopic theory of flexoelectricity and the drift-diffusion theory of semiconduction are used. They are coupled by doping and mobile charges in Gauss's equation of electrostatics. A one-dimensional electromechanical model is established

This work discusses an optical system with brightness amplification—a laser monitor, as well as the system's application for real-time imaging of the surface of metal nanopowders during high-temperature combustion. The advantage of the laser monitor is its combination of microscopic magnification, laser backlighting, and narrow-band filtering, which, together with high-speed video recording, makes

In this work, a new model for the mobility due to Coulombic scattering by interface charges ( μ C) in 4H-SiC MOS structures, which is suitable for device study via finite element (FE)-based simulations, is proposed. Unlike popular expressions based on the classical Sah–Lombardi model which lead to major inconsistencies in μ C’s variation with the semiconductor depth z, the proposed model combines previous