Applied Physics A最新文献

The plasma and resonance frequencies are the electrical and optical properties, which are related to material dispersion and propagation of the electromagnetic wave through dielectric media. They are normally regarded as two independent parameters. The energies of the resonator and plasmon are conserved. Propagation of the conserved property obeys a wave equation. A general solution for the wave equation is expressed as the Fourier series of the infinite harmonic functions of the phase, which connects the wave equation with Planck’s distribution function. The energy quantization is a mathematical consequence of the Fourier series of the kinetic energy. It is experimentally confirmed by the observed overtone bands in the infrared spectra of crystals. Using Parseval’s relation allows one to calculate the eigenenergy of an elastic mode. Since the resonator and plasmon have different mode numbers, this feature leads to a linear relationship between the resonance and plasma frequencies. Experimentally, the temperature-dependent resonance and plasma frequencies can be determined by measuring the material dispersion. The proposed relationship was confirmed by measuring material dispersion of silica glass at different temperatures.

This theoretical study investigates the nanomechanical behavior and fracture dynamics of PCF-graphene single layer and nanotubes, focusing on the influence of nanostructural parameters such as length, diameter, as well as external factors like temperature effects. Using the reactive (ReaxFF) classical molecular dynamics simulation method by using the LAMMPs code is employed to estimate nanomechanical properties like Young’s modulus, ultimate tensile strength, and critial strain by simulating the atomic-level response of a PCF-graphene-based 1D and 2D to applied uniaxial forces. The Young’s modulus, ultimate tensile strength, and critical strain are shown to vary significantly with nanostructural scaling, demonstrating distinct effects on nanomechanical properties compared to single layer and single-walled nanotubes PCF-graphene nanostructures. Temperature studies further reveal that thermal softening degrades nanomechanical performance. Our results showed that the Young’s Modulus for PCF-graphene single-layer for uniaxial strain in the x-direction ranges from (5651.7 - 4328.6) GPa.Å and in the y-direction (2408.5 - 1934.4) GPaÅ. The Young’s modulus of the PCF-G-NTs ((0, n) and (n, 0)) are range (1850.5 - 2603.3) GPaÅ and, (386.25 - 1280.7) GPaÅ respectively. The Poisson’s coefficients value are 0.20 and 0.48 for PCF-G-NTs (6, 0) and (0, 7), respectively. These findings provide critical insights into the anisotropic nanomechanical behavior of PCF-graphene 1D and 2D, offering a foundation for optimizing their design for applications in nanocomposites, nanoelectromechanical systems, and other advanced materials requiring tailored mechanical properties. We believe that the new results presented to the scientific community in nanoscience can contribute to a theoretical library for future applications of the PCF-graphene nanostructure in the sustained development of new carbon-based materials.

This study investigates the reflection of plane waves in an initially stressed rotating orthotropic microstretch thermoelastic half-space within the frameworks of Lord–Shulman (LS) and Green–Lindsay (GL) theories. A complete mathematical model is formulated to describe the coupled effects of displacement, microrotation, microstretch and thermal fields. When a quasi-longitudinal displacement (qLD) wave strikes the stress-free thermally insulated boundary it generates five reflected wave modes: qLD, quasi-transverse displacement (qTD), quasi-transverse microrotational (qTM), quasi-longitudinal microstretch (qLM) and quasi-thermal (qT) waves. Analytical expressions for phase velocities, reflection coefficients and energy ratios are derived and these quantities are evaluated numerically. Graphical results are used to study how initial stress and rotation influence the phase velocity and reflection coefficients. The graphical results reveal significant differences between LS and GL theories particularly in the behavior of phase velocity and reflection coefficients under initial stress and rotation. The study demonstrates that thermal relaxation times in the GL theory considerably alter the reflection patterns while the LS theory shows stronger sensitivity to mechanical effects. To establish the accuracy of the formulation the governing equations are reduced by setting initial stress, rotation and thermal parameters to zero. In this limiting case, the model exactly agrees with the pre-established results which confirms the correctness of the derived boundary-value system. A benchmark comparison table and graphical evaluation further validate the present results. The findings provide new insights into wave propagation in micro-structured thermoelastic media and offer a reliable framework for applications in geophysics, materials engineering and advanced wave-based analysis.

This study presents a comprehensive theoretical model to analyze the nonlinear vibration behavior of an adatom-microstructure system subjected to coupled magneto-thermal fields designed for high-performance mass sensing applications. The analyzed configuration is a sandwich microbeam featuring functionally graded carbon nanotube-reinforced composite (FG-CNTRC) face sheets with a perforated core featuring a periodic square-hole (PSH) lattice. Four CNT distributions uniform (UD) and functionally graded FG-A, FG-V, FG-X are evaluated using the mixture rule for effective properties. The size-dependent response of the FG-CNTRC sandwich microbeam is investigated using non-local strain gradient theory, while the geometric nonlinearity is addressed using the nonlinear von Karman hypothesis. The van der Waals (vdW) forces between the adatoms and the microstructure substrate are modeled by the Lennard-Jones (6–12) potential. Lorentz forces from the magnetic field are incorporated via Maxwell’s equations. The governing nonlinear partial differential equation, formulated within the Euler–Bernoulli and Levinson beam theories, is reduced via the Galerkin procedure to a fourth-order ordinary differential equation containing cubic nonlinear terms. This reduced-order model is then solved analytically using the multiple-scales method to obtain the nonlinear resonance frequency shift. Numerical results reveal strong sensitivity of the nonlinear frequency to the CNT distribution scheme, perforation geometry, magnetic-thermal loading, and nanoscale effects. The combined multiphysical and structural effects enable substantial tunability of the resonance characteristics. These findings highlight the potential of the proposed FG-CNTRC perforated micro-resonator as a highly sensitive and tunable platform for advanced micro/nano-electro-mechanical mass-sensing applications.

1T metastable state of MoS₂ has drawn attention in Lithium-ion batteries (LIBs) due to its superior electronic conductivity and more active sites. In this paper synthesis of 1T-2 H MoS₂ using a facile one-step hydrothermal method has been attempted. X-ray diffraction (XRD) confirms the pure MoS₂ phase, however, Raman spectroscopy shows the 1T-2 H MoS₂ phase with a slight presence of intermediate product MoO₃ which is due to the synthesis routes. Scanning Electron Microscopy (SEM) displays the formation of nano-flowers as well as Energy Dispersive X-ray Spectroscopy (EDX) confirms the presence of Mo, and S elements is higher in the ratio in comparison to O element due to the ratio of precursors taken. The as-prepared MoS₂ has been tested as an anode material for Lithium-ion Batteries (LIBs). Cyclic Voltammetry (CV) results depict the MoS₂ material exhibits excellent stability by tracing the same voltage profile after the initial cycle. Rate performance shows that discharge capacities are about 882.76, 560.02, 442.54, 347.83, 240.35, and 438.70 mAh g^− 1 at varied current densities of 100, 200, 500, 1000, 2000, and back to100 mA g^− 1 respectively. Galvanostatic charge-discharge performance shows the reversible nature of MoS₂ electrodes with high coulombic efficiency (~ 98%) even after 300 cycles.

We present a comprehensive investigation into the localized surface plasmon resonance (LSPR) properties of gold (Au), silver (Ag), and titanium nitride (TiN) nano cube monomers and homodimers. Utilizing FDTD simulations, we systematically varied geometrical parameters including particle size (20–60 nm), interparticle gap (2–10 nm), orientation (tip-to-tip vs. edge-to-edge), and surrounding refractive index (n = 1.0–1.5) to unravel their influence on extinction spectra and near-field enhancement behaviour. Silver nanocubes consistently emerged as the superior performer, delivering the strongest field localization (> 100×), sharp and tunable resonance peaks, and rapid spectral shifts under both gap and environmental tuning. Gold offered a balanced alternative, achieving moderate enhancements (~ 15–70×) with stable performance and narrow resonance bandwidths. Remarkably, TiN, despite its broader and more damped plasmonic response, demonstrated unexpectedly high refractive index sensitivity surpassing Ag and Au when examined in edge-polarized or corner-focused configurations (RIS ~ 309 nm/RIU). This sensitivity is attributed to corner-induced field concentration and confirms the validity of plasmon hybridization in tip-to-tip and edge-to-edge assemblies, which produce intense “hot spots” whose spectral and spatial characteristics depend sensitively on gap distance and dielectric environment. Our results guide the strategic design of plasmonic nanodevices: Ag dimers for ultra-sensitive field-driven applications (e.g., SERS, hot-electron generation), Au structures for reliable performance with minimal degradation, and TiN geometries for robust and tunable sensing in demanding operational environments.

Neodymium oxide (NdOₓ) is a promising switching material for nonvolatile resistive random-access memory (RRAM), yet its behavior on flexible substrates under mechanical stress remains insufficiently explored. In this work, NdOₓ thin films were deposited by rf magnetron sputtering onto ITO/glass and flexible ITO/PEN substrates to form Al/NdOₓ/ITO metal–insulator–metal structures. Baseline evaluation on ITO/glass identified optimal sputtering conditions of 100 W, 20 min deposition, and 4% oxygen, yielding low operating voltages (VSET ≈ 1 V, VRESET ≈ 1 V), endurance of 100 cycles, and retention exceeding 10⁴ s. Mechanical reliability was further assessed on flexible substrates under bending radii of 1–5 cm. The best performance occurred at a curvature radius of 5 cm, maintaining stable bipolar switching for ~ 120 cycles, attributed to strain-modulated filament formation. These results confirm that NdOₓ films enable reliable, low-voltage switching on both rigid and flexible platforms, demonstrating strong potential for future wearable and deformable nonvolatile memory applications.

Un-doped NiCr₂O₄ and Sn-V co-doped NiCr₂O₄ nanoparticles with varying doping concentrations (2%, 3%, and 4%) were synthesized and characterized using various analytical techniques. X-ray diffraction (XRD) analysis confirmed the formation of a single-phase spinel structure with slight peak shifts indicating successful incorporation of Sn and V into the NiCr₂O₄ lattice. The crystallite size was found to slightly decrease with increasing dopant concentration due to lattice distortion. Diffuse Reflectance Spectroscopy (DRS) revealed a gradual reduction in the optical band gap from pure NiCr₂O₄ (∼2.54 eV) to 4% doped samples (∼2.42 eV), indicating enhanced visible-light absorption. FTIR spectra displayed characteristic vibrational bands of metal-oxygen stretching modes, with minor shifts upon doping due to lattice modification. Photoluminescence (PL) studies showed a quenching effect in the doped samples, suggesting reduced electron-hole recombination and improved charge separation. SEM images revealed that all samples exhibited agglomerated but well-dispersed nano spherical morphology, with smaller particle sizes observed in higher dopant levels. Photocatalytic application was studied upon degrading rhodamine B (RhB) and methylene blue (MB) textile dyes. 3wt% Sn-V: NiCr₂O₄ degrades 84% of RhB and 88% of MB in 100 min.

SnO(_{varvec{2}}) exhibits a wide bandgap ((sim)3.6 eV) and a high exciton binding energy at room temperature, along with visible light transmittance exceeding 90%. Due to its unique optical, electrical, and stable physicochemical properties, it has been widely applied in various fields. In this study, we employed the hybrid functional HSE06 method within first-principles calculations to investigate the electronic structure and optical properties of intrinsic SnO(_{varvec{2}}) as well as Pd-, Dy-, Gd-, Sm-, Ru-, Nd-, and Mo-doped SnO(_{varvec{2}}) systems. Through these calculations, we obtained the electronic structure and optical properties (such as reflectivity and absorption spectra) of both doped and undoped systems. Based on the accurately computed band structures and density of states, we analyzed the related electronic and optical properties. The results demonstrate that the HSE06 method accurately predicts the bandgap of SnO(_{varvec{2}}), yielding values in close agreement with the experimental value of 3.6 eV. Furthermore, Dy- and Gd-doped SnO(_{varvec{2}}) systems exhibit improved optical performance and enhanced electrical conductivity. With respect to optical properties, rare-earth doping (Nd, Sm, Gd, Dy) induces a redshift in the absorption edge, thereby extending the spectral response range. Compared to intrinsic SnO(_{varvec{2}}), the static dielectric constant decreases in the Nd-doped system but increases upon Sm, Gd, and Dy doping, which is beneficial for future research and application in optoelectronic devices.

In the framework of the density functional theory with gradient functionals PBE and PBEsol in the basis of localized orbitals of the CRYSTAL package, ab initio studies of the crystal structure, electronic structure, vibrational spectra and linear, and nonlinear optical coefficients of crawfordite Na₃Sr(PO₄)(CO₃) under pressure are performed. In this structure, sodium and oxygen atoms occupy nonequivalent positions, and it leads to their different charge states and different strengths of chemical bonding in anions [PO₄]^−2.29 and [CO₃]^−1.49, as well as a special structure of the upper valence and lower unoccupied bands. The vibrational modes of the anions dominate in the spectra of infrared absorption and Raman scattering. Under pressure, the refractive indices increase, while the second harmonic generation efficiency becomes less than 0.67×KDP. The structure and properties of designed Na₃Pb(PO₄)(CO₃) crystal with a crawfordite structure, in which the SGH efficiency is 2.3 times greater than that of KDP, are calculated.