New Publications

https://doi.org/10.1364/AO.568733

Developing tunable photodetectors that can operate over a wide range of wavelengths and integrating them into integrated circuits is a significant challenge in today’s technology. These devices must be miniaturized, inexpensive, and easily manufactured. To address this challenge, we propose the development of a tunable planar hot-electron photodetector based on Tamm plasmon-polariton. Operational wavelength tuning is achieved by incorporating a material with a phase transition, Sb2S3, into a Tamm plasmon-polariton-based structure. This allows for tuning the detection wavelength over a broad range encompassing all bands of the telecommunications spectrum.

 https://doi.org/10.1002/jrs.70001

This study examines the temperature-dependent Raman spectra of MBE-grown bismuth telluride (Bi₂Te₃) thin films, analyzing Stokes, and anti-Stokes scattering in two polarizations to resolve symmetry-dependent mode strengths. Density functional theory simulations of Stokes spectra identified the fundamental vibrational modes and anharmonic decay. The temperature evolution of phonon wavenumbers and linewidths revealed the role of anharmonicity: the real part of the phonon self-energy governs the wavenumber shift (redshift) of the A1⁢�2 mode, while its imaginary part drives the linewidth broadening, both arising from cubic and quartic anharmonic processes which is associated to energy and symmetry of the mode. In contrast, the lower wavenumber A1⁢�1 and E�2 modes exhibited weaker coupling to thermal decay channels, reflected in smaller changes to their self-energy components and longer lifetimes. The intensity of A1⁢�2 mode decreased significantly with temperature due to multi-phonon decay, whereas A1⁢�1 and E�2 intensities remained stable. These results quantify the distinct mediation of wavenumber renormalization and lifetime effects in Bi₂Te₃ by the real and imaginary components of the phonon self-energy.

https://doi.org/10.22184/1993-7296.FRos.2025.19.4.304.311

Time-dependent density functional theory-based approaches, TD-DFT and TD-DFTB, are used to study the optical absorption of B800 part of light-harvesting complex 2 (LH2) of Rhodoblastus acidophilus. Calculated spectra for both single molecule and the optimized structure of B800 complex containing nine of such molecules are in qualitative agreement with experimental data. The absence of any sizable effects originating from the interaction between adjacent molecules are proved. Thus, optical features of B800 LH2 part are not connected to the structural organization of pigments. The importance of the time-dependent procedure for the correct description of BChl a absorption spectrum is demonstrated.

При помощи нестационарных расчетов на основе теории функционала плотности методами TD-DFT и TD-DFTB исследованы оптические свойства фрагмента B800 светособирающего комплекса 2 (LH2) Rhodoblastus acidophilus. Полученные в результате расчетов спектры поглощения как одиночной молекулы BChl a, так и оптимизированной структуры B800, состоящей из 9 молекул, качественно согласуются с экспериментальными данными. Доказано отсутствие значимых эффектов, обусловленных взаимодействием между соседними молекулами. Таким образом, спектральные особенности B800 не связаны со структурной организацией молекул пигментов. Показана важность нестационарных расчетов для корректного описания спектра поглощения BChl a.

https://doi.org/10.1007/s11051-025-06271-9

The paper provides a comprehensive analytical and numerical examination of the properties of single-domain superparamagnetic magnetite nanoparticles, aiming to devise strategies for selectively damaging the membranes of malignant cells and enhancing anticancer magnetomechanical therapy. It highlights the potential formation of anisotropic aggregates composed of multiple magnetite nanoparticles even in the absence of an external magnetic field. These aggregates, when combined with gold nanoparticles, can selectively bind to mechanoreceptors on the membranes of malignant cells employing aptamers. The aggregation process suppresses thermal fluctuations of the intrinsic magnetic moments of individual particles, thanks to the collective magnetic field generated by the resulting subaggregates. As a result, these nanoparticle aggregates demonstrate stabilization of their total magnetic moment driven by this cooperative behavior. The growth of aggregates of magnetic nanoparticles is accompanied by an increase in the total magnetic moment of the aggregates and the strength of the mechanical effect on cell mechanoreceptors. This enhanced interaction can contribute to the programmed death of malignant cells (apoptosis) in malignant cells when exposed to an alternating magnetic field. The analysis presented makes it possible to explain the experimental results from magnetomechanical therapy utilizing gold and magnetite nanoparticles, which effectively suppresses Ehrlich carcinoma both in vivo and in vitro within an alternating magnetic field. These results affirm the promising potential for implementing this method as a highly effective treatment for malignant tumors.

https://doi.org/10.1007/s10948-025-07025-3

The magnetization of a series of samples containing ε-Fe₂O₃ nanoparticles of different average sizes (approximately 4‒11 nm) has been measured in the temperature range of 300–550 K, which includes the region of a high-temperature magnetic transition. The observed Néel temperature drop has been attributed to the manifestation of the size effect: from ~ 500 K for fairly coarse (> 10 nm) particles to ~ 450 K for particles of ~ 5 nm in size. The obtained particle size dependence of the Néel temperature has been analyzed within the scaling law for critical phenomena in finite-size systems.

https://doi.org/10.1016/j.tsf.2025.140746

The synthesis of vanadium oxide compounds, V₂¹⁸O_3-x, with oxygen non-stoichiometry and heavy oxygen isotope doping (¹⁸O), was achieved via the cathode arc sputtering method. The microstructural characteristics and stoichiometric properties of the resulting nanocrystalline films were examined using X-ray diffraction, atomic force microscopy and Rutherford backscatter spectrometry. The concentration of defects leading to the suppression of the structural and electronic metal-insulator transition was evaluated through Raman spectroscopy and the analysis of electrophysical properties. A semi-empirical simulation of the lattice dynamics of vanadium oxide was also performed. Notable temperature anomalies in resistance, impedance, and relaxation time were observed. A model involving the deformation of octahedra and the splitting of oxygen vacancies multiplets was proposed to explain the formation of impurity subbands. Furthermore, a change in the sign of magnetoresistance and magnetoimpedance at specific temperatures, along with the effect of photoconductivity, was discovered.

DOI 10.3897/j.moem.11.2.141803
The paper studies the effect of high-temperature treatment on structural and magnetic properties of the system MnZn_1-xCr_xSb (0 ≤ x ≤ 0.20) solid solutions obtained by solid-phase reactions with subsequent quenching. It was shown all solid solutions have a tetragonal crystal structure with P4/nmm space group, which is preserved under high-temperature treatment. The temperatures of the magnetic phase transition increase with grow substitution concentration. High-temperature treatment of the initial MnZnSb compound leads to increasing of Curie temperature and coercive force. The effect of substitution concentration on the coercive force and magnetization value has been discovered.

DOI: 10.3367/UFNr.2024.06.039696

Рассмотрены экспериментальные и теоретические результаты по изинговской сверхпроводимости. Данное направление в физике сверхпроводимости началось с обнаружения необычной сверхпроводимости в слоистых дихалькогенидах переходных металлов типа MoS₂ с необычно большими значениями верхнего критического поля B_c2, в шесть раз превышающего парамагнитный предел. Оказалось, что это обусловлено особенностями кристаллической решётки двумерных монослоёв, индуцирующих спин-орбитальные взаимодействия Изинга и Рашбы. Особенности кристаллической структуры приводят к сосуществованию синглетного и триплетного спаривания, а также к топологическим фазам. Обсуждаются варианты поиска майорановских состояний на концах одномерных проводов на поверхности изинговского сверхпроводника.

https://doi.org/10.1134/S1063784225700264

The parameters of a resonator consisting of two dielectric plates with gratings of strip conductors between the layers in the form of squares, and on the outer surfaces in the form of square meshes having the same subwavelength period, have been determined. The quality (Q) factor of the resonator, which has been measured at the normal wave incidence, is determined by the ratio of the widths of the internal and external conductors. Using electrodynamic analysis of a 3D resonator model, the propagation of plane linearly polarized electromagnetic waves when their angle of incidence φ deviates from the normal to the plane of the layered structure has been studied. It is found that for the parallel polarization of the wave, the Q factor of the observed half-wave resonance with increasing φ first drops to a minimum when approaching the Brewster angle, and then increases as φ → 90°. In the case of the perpendicular polarization of the wave, the Q factor of the half-wave resonance gradually increases with increasing φ, approaching the maximum value at φ → 90°.

https://doi.org/10.1134/S0021364025606396

The features of the magnetic structure of ultrasmall �-Fe₂O₃ nanoparticles have been studied by the nuclear forward scattering technique using synchrotron radiation. The sample consists of isolated �-Fe₂O₃ nanoparticles with an average size of ⟨�⟩=3.8 nm immobilized in a SiO₂ xerogel matrix. The time-domain spectra have been measured in the temperature range of 4–300 K in zero external magnetic field and field �=4 T applied in the longitudinal direction. The character of the change in the hyperfine field H_hf as a function of the external magnetic field is the same in the entire temperature range: unlike large �-Fe₂O₃ particles, a monotonic increase in H_hf is observed in the external field. These results indicate that there is no magnetic transition in the temperature range of 80–150 K for ultrasmall (smaller than ≈9 nm) �-Fe₂O₃ particles, and the magnetic structure is noncollinear in the range of 4–300 K.

https://doi.org/10.1063/5.0264288

The work proposes a model for analyzing oscillations of charge carriers in systems consisting of a single metal nanoparticle located on a graphene monolayer and excited by an electromagnetic pulse directed normally to the graphene surface. Unlike previous studies where graphene served only as a conductive medium for charge transfer between metal nanoparticles, here we focus on the direct interaction between a metal nanoparticle and graphene. This includes studying nanoparticle–graphene charge transfer dynamics and carrier distribution in graphene. For systems containing nanoparticles of different radii, it is shown that the real part of the frequency of the graphene charge density fluctuations is approximately 6.5×1014 Hz, while the imaginary part of the frequency dominates the real part. Graphene interband conductivity is also shown to be critical.

DOI: 10.18083/LCAppl.2025.2.89

Understanding the molecular nature of ferroelectric nematics N_F can be aided by the following information: the anisotropy of the pair correlation function g₂(r) of intermolecular distances r, averaged over the orientations of molecules; the degree of orientation ordering of molecules S with respect to director n; the molecular polarizability components γ_j averaged over the molecular ensemble in the director's coordinate system with axes parallel (j = ||) and perpendicular (j = ⊥) to the n-axis. For a uniaxial liquid crystal (LC), the key to this information is provided by the experimental values of the Lorentz tensor components L_j. The components f_j(λ) of the local-field tensor of light wave with the wavelength λ depend on the components L_j. In this work, the experimental values of the components L_j and the components P_j = γ_j/v (where, v is the volume per molecule in the medium) of the polarizability density of molecules were determined for a ferroelectric nematic mixture FNLC919 with known refractive indices n_j(λ) in the transparency range λ = 0,4 ÷ 0,75 μm at room temperature. Taking into account the anisotropy of the components L_j, the anisotropy of spheroidal surface F(r) was found, which meets the condition g₂(r) = const and characterizes the local anisotropy of the LC. Similar and distinguishing features of the components L_j, f_j(λ) for the FNLC919 mixture in comparison with those for nonpolar nematics and other uniaxial media were noted. A relationship between the anisotropy of the L_j components and the temperature dependencies of n_j(T) in the N_F phase was established. This relationship correlates with the change of n_j(T) in the N_F-phase of the other known mixture M5. The constraints on the mean value and the anisotropy of the components P_j(λ) have been set. These constraints are due to the anisotropy of the components f_j(λ). The spectral features of the P_j(λ) functions and their implications were elucidated.

https://doi.org/10.1016/j.ceramint.2025.06.356

―A new Sn₃Mo₂O₈ compound was synthesized and its crystal structure was determined. A Sn₃Mo₂O₈/Bi₂₆Mo₁₀O₆₉ (89 %/11 %) composite was obtained by the solid-state synthesis. Vibrational modes of octahedra and temperatures of softening and disappearance of some modes from the IR absorption spectra in the temperature range of 80–500 K and the frequency range of 350–7000 cm⁻¹ was found. A correlation was established between the temperatures of the thermopower maxima and softening of IR modes, and anomalous in the temperature coefficient of resistance, impedance, which was explained within the displacement-type phase transition model. The activation energy and temperature range of the ionic conductivity in the Sn₃Mo₂O₈ compound was determined.

 https://doi.org/10.1002/andp.202500080

Complex optical vortex bundles produced by dislocations arranged in accordance with the group of symmetry �1,�2,�4 are studied theoretically and experimentally. The spatial evolution of optical vortices is investigated for three types of spatial configurations based on the signs of dislocation topological charges. Theoretical predictions derived from the Fresnel diffraction integral and the hydrodynamic approach have been found to be consistent with each other and are in a good agreement with the experimental results. For all cases, the symmetry properties of the dislocation arrangement are shown to be imposed to optical vortex bundles produced. The observed dynamics provides new insights into the behavior of singularities in complex optical fields.

https://doi.org/10.5599/admet.2723

Background and purpose
Polyhydroxyalkanoates (PHAs) are biodegradable polyesters of bacterial origin that are actively studied as matrices for the preparation of nanoparticulate drug delivery systems. The most significant parameters affecting PHAs nanoparticles (NPs) characteristics are polymer composition and the type of surfactant used to stabilize the emulsion during NPs preparation. However, there are only a few studies in the literature investigating the effect of these factors on the characteristics of PHA NPs.
Experimental approach
Blank poly(3-hydroxybutyrate) (P3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P3HBV) NPs were produced and characterized in terms of their size, morphology and zeta potential. Poly(vinyl alcohol) (PVA) with various molecular weights (31-50 and 85-124 kDa), as well as Tween 20 (TW20), Tween 80 (TW80), sodium deoxycholate (SDC) and sodium dodecyl sulphate (SDS) were used as surfactants. For NPs that formed stable aqueous suspensions and had the most desirable characteristics (P3HB/PVA31-50 and P3HBV/PVA31-50), hemolytic activity and cytotoxicity to HeLa and C2C12 cells in vitro were determined.

https://doi.org/10.1134/S0021364025606244

It has been shown that the Kohn‒Luttinger superconductivity mechanism interplaying with other types of ordering can be implemented in systems with a hexagonal lattice. A number of unusual properties of such systems in the normal phase have also been considered. Our previous results on Kohn‒Luttinger superconductivity with p, d-, and f-wave pairing in monolayer and AB bilayer graphene, obtained disregarding the effect of substrate potential and impurities, have been presented in the first part. Then, the interplay of the superconducting Kohn‒Luttinger state with the spin density wave state in actual AB, AA, and twisted bilayer graphene has been discussed in detail. In the last parts, a number of anomalous properties in the normal phase and the appearance of nematic superconductivity alongside with the spin density wave in the twisted bilayer graphene have been presented.

https://doi.org/10.1016/j.jallcom.2025.181497

In the Co₃O₂BO₃ Ludwigite, there are four crystallographic sites for the metal ion Co. Three sites are occupied by Co2+ in a high-spin state, and one site by Co3+ in low-spin state, resulting in a compound where the number of Co2+ ions is twice that of Co3+ ions. Given the particular distribution of magnetic and non-magnetic ions, the compound can be visualized as consisting of magnetic planes containing Co2+ ions, separated by non-magnetic planes formed by Co3+ ions. In this work, were studied the structural changes, especially magnetic ones, caused by the gradual substitution of low-spin Co3+ (S=0) by Cr^3＋ ions (S = 3/2). We synthesized the Co3−�Cr�O₂BO₃ series, and X-ray experiments showed a gradual increase in unit cell volume with increasing Cr concentration. Magnetization measurements show that this type of substitution drastically increases the magnetic transition temperature, from 42 K for the undoped compound to 115 K for the compound with the highest Cr concentration. The latter is the highest long-range magnetic ordering temperature recorded so far for cobalt Ludwigites. The results from specific heat and magnetization measurements show that this substitution changes the ground-state magnetic structure of the compound, transitioning from a ferrimagnetic state (at low Cr concentrations) to an antiferromagnetic state (at high Cr concentrations), in agreement with the results of exchange integral calculations.

https://doi.org/10.1016/j.jallcom.2025.181990

Magnetic circular dichroism (MCD) spectroscopy in the range of 1.2–3.7 eV was studied for La_1-xK_xMnO₃ (x = 0.05–0.18) epitaxial films over a wide temperature range. The thin films were grown using a two-step procedure: deposition of La_xMnO_3-δ and potassium K⁺ incorporation into the films via isopiestic annealing. The temperature behavior of the MCD effect in different spectral regions was analyzed alongside the temperature dependences of magnetization, resistivity, and magnetoresistance of the films. It was found that the MCD signal is sensitive not only to the magnetic but also to the charge sublattice of the material. Accordingly, a correlation between the magneto-optical and magnetoresistive responses of the system was identified. These findings underscore the high information content of MCD spectroscopy for investigating the magnetic and magnetotransport properties of strongly correlated magnetic oxides. The ground and excited electronic states in the La_1-xK_xMnO₃ films were identified, and the obtained data were compared with magneto-optical data for divalent - doped and lanthanum-deficient manganite films. Good agreement was observed, indicating the universality of the electronic structure and the shared mechanisms underlying the observed effects in such materials. These results broaden the understanding of the band structure in manganites and provide a solid foundation for its theoretical description.

https://doi.org/10.1016/j.physb.2025.417507

The density functional theory simulations of the electronic band structure of the Li2K4TiOGe4O₁₂ crystal of the tetragonal phase were carried out along the high-symmetry directions of the Brillouin zone. The simulation partial density of states of the crystal in the P4nc phase was performed to describe the origin of the electronic bands. The optical linear (dielectric function, conductivity, refractive index, absorption, loss function, and reflectivity) and nonlinear properties of the crystal (susceptibility tensor elements) were calculated. The article compares the properties of this crystal with those of other nonlinear crystals. The dispersion of phonons and Raman spectrum were also calculated, and the stability of the crystal phase was demonstrated.

https://doi.org/10.1016/j.jpcs.2025.112977

At ambient pressure and temperature, Raman spectroscopy showed A₁, E and T₂ modes in HgSe which suggested coexistence of zinc blende (zb) and cinnabar (cin) phase. A blue shift of A₁ and E Raman modes was observed with increasing temperature, which was explained by the reduction of lattice constant. Experimental results of Raman spectroscopy were consistent with the DFT calculation, both predicted transition to cin phase at moderate pressure of 1.5–1.8 GPa, and a complete absence of the Raman modes was observed above pressure of 16 GPa, confirming the transformation to the NaCl structure. The pressure-dependent frequency shift, linewidth and Raman intensity was explained by eigenvectors of vibrational symmetry of the modes, anharmonic effect and changes in polarizability.

https://doi.org/10.1134/S0020441225700071

An inspection probe is the key component of a scanning ferromagnetic resonance spectrometer, which is used to measure spectra of electromagnetic radiation absorption in local areas of thin magnetic films. The degree of locality is determined by the area of the measuring aperture in a probe (0.1–2.2 mm²). The spectrometer sensitivity has been significantly increased by miniaturizing the oscillating circuit with a high intrinsic quality factor of the autodyne oscillator and by replacing the round measuring aperture of the probe head with a square one. The square shape of the measuring aperture increases the homogeneity of the high-frequency magnetic field distribution in it. A set of replaceable probes with a required pitch has been designed to cover the frequency range of 0.1–4.0 GHz. The signal-to-noise ratio of a probe with an aperture area 1.0 mm², measured on a permalloy film with a thickness of 2 nm is 8 dB or more. It is shown that the effective saturation magnetization monotonically reaches the saturation M_S = 843 G with frequency rise and abnormally increases by a factor of ~1.6, to M_S = 1359 G at low frequencies. The applicability of the developed probes to study the nature of formation and the peculiarities of the magnetic-inhomogeneity distribution over a sample area is demonstrated by using 25-nm-thick permalloy films (dimensions, 10 × 10 mm²) deposited in a dc magnetic field on monocrystalline langasite substrates.

https://doi.org/10.1134/S2075113324701648

Features of the defect structure of a nominally pure LiNbO_3stoich crystal and double-doped LiNbO₃:Zn:Mg (3.45:1.41 mol %) and LiNbO₃:Zn:Mg (3.45:1.22 mol %) single crystals have been studied using Raman spectroscopy, infrared absorption spectroscopy, photoluminescence, laser conoscopy, and photoinduced light scattering. The material for the study has been obtained using homogeneous and direct doping technology. It has been shown that double-doped LiNbO₃:Zn:Mg crystals obtained using different technologies have high resistance to damage by laser radiation. However, the LiNbO₃:Zn:Mg (3.45:1.22 mol %) crystal obtained by direct doping technology is characterized by lower compositional uniformity compared to the LiNbO₃:Zn:Mg (3.45:1.41 mol %) crystal obtained by homogeneous doping technology. Raman spectra have showed that the features of the defect structure of double-doped LiNbO₃:Zn:Mg crystals are largely determined by the magnesium impurity. This may be the reason that the influence of the ordering mechanism of magnesium cations (~1.22–1.44 mol %) prevails over the influence of the disordering mechanism of zinc cations (~3.45 mol %) on the features of the structural units of the cation sublattice. It has been found that the lowest concentration of OH groups and photoluminescence intensity in the near-IR region is characteristic of the LiNbO₃:Zn:Mg (3.45:1.41 mol %) crystal obtained by homogeneous doping technology.

https://doi.org/10.1016/j.microc.2025.114358

Miniature electronic sensors manufactured using modern silicon technology have been intensively studied as candidates for replacing chemical and biological test systems used in medicine for precision detection of proteins and molecules in liquids and gases. Selective recognition of low concentrations of biomarkers will make it possible to diagnose dangerous diseases at early stages, thereby ensuring their successful treatment. In this study, a method for electrical detection of a heart-type fatty acid-binding protein (hFABP) in air is proposed. To enhance the selectivity, silicon nanowire field-effect transistors (Si-NW FETs) with channel widths of 0.4, 1, and 3 μm have been fabricated and pre-functionalized with an anti-hFABP DNA aptamer (FABPAp1c-t38). It has been found that the FABPAp1c-t38 and hFABP protein induce opposite shifts of threshold voltage V_th of the Si-NW FET. For a detected target, the voltage V_th shifts from +0.2 to +2.8 V. It has been established that the voltage V_th is a better signal as compared with other electrical characteristics of the transistor. This has allowed the hFABP detection at concentrations of 1 pM in a model buffer system. It is expected that the proposed cardio target sensors and method for detection under dry conditions will contribute to the development and production of various electronic devices for application in medicine and other fields.

https://doi.org/10.1016/j.jmmm.2025.173283

To determine the direction of DM vector in the magnets with two non-coplanar super-exchange paths, a criterion based on an asymmetry of distribution of ligands between interacting spins is proposed. The direction of DM vector in PbMnBO4 corresponds to structural formula following from this criterion. The exchange paths, allowing the existence of the two-bridge DM interaction between neighboring Mn3+-ions in the chains, are considered. The possible mechanisms of antisymmetric exchange via two ligands in this crystal are discussed.

DOI:https://doi.org/10.48084/etasr.9547

This work studies a ceramic material, synthesized from alumina nanofiber via semi-dry pressing with an average diameter of 10 nm and a high aspect ratio (>1000), with Hydrofluoric Acid (HF) used as a mineralizer. The effects of varying firing temperature and HF concentration were systematically investigated. The material was characterized using electron microscopy, X-ray fluorescence analysis, and X-ray phase analysis, while thermodynamic calculations of phase transformations were conducted. Additionally, strength, density, and open porosity were analyzed as functions of the processing parameters. The analysis revealed that an optimal HF concentration of 1% and a firing temperature of 800 °C yield the best physical and mechanical properties. Furthermore, the transition mechanism from the γ-phase to the α-phase under varying HF concentrations and firing temperatures was examined. A linear dependence of the concentration of Fluorine (F) atoms in the ceramic material on the firing temperature was established. The maximum physical and mechanical characteristics include a compressive strength of 49 MPa with a porosity of 46% and a density of 1.47 g/cm³.

https://doi.org/10.1002/slct.202500964

A substitutional solid solution of (Gd_0.94Ce_0.03Tb_0.03)₂O₃ (Ia, a = 10.8496 (5) Å, V = 1277.1 (2) Å³) was obtained by hydrothermal synthesis from rare earth nitrates and sodium hydroxide, followed by calcination in air at 900 °C for 2 h. The subsequent sulfidation of the compound in a hydrogen sulfide stream at 900 °C for 9 h yielded a substitutional solid solution of the oxysulfide (Gd_0.94Ce_0.03Tb_0.03)₂O₂S (Pm1, a = 3.8682 (4) Å, c = 6.6770 (8) Å, V = 86.52 (2) Å³). A qualitative and quantitative analysis of the obtained samples was carried out using the Rietveld method, along with morphological characterization of the particles. A mechanism for the transformation of particles at different stages of synthesis has been proposed. Combined experimental and theoretical investigations showed possibility of both direct and indirect electronic transitions in (Gd_0.94Ce_0.03Tb_0.03)₂O₂S. Density functional theory calculations highlighted the complex nature of charge transfer in lanthanide oxysulfides, suggesting further investigations. The results of the study on the photoluminescent properties of the obtained phosphors showed that Tb³⁺ ions play a major role in the emission processes, with the most intense emission band occurring in the green spectral region at 538 nm. In addition to the narrow terbium bands, weak cerium emission was also observed, covering a broad spectral range of 350–700 nm.

https://doi.org/10.1002/andp.202500089

The enhancement of surface plasmon polariton (SPP) gain and propagation length at optical frequencies on the interface between a metal film and a medium with Raman gain, in the presence of a coherent control field, is theoretically investigated. It is shown that the Raman interaction between the SPP excitation field and the control field can provide gain sufficient for lossless SPP propagation. This interaction reduces the requirement for the SPP excitation field. It is shown that a significant increase of the propagation length can be achieved in the case of lossy propagation. By varying the intensity or frequency of the control field it is possible to control the SPP. Optical control of the dynamics of SPP propagation by means of an external coherent field in the Raman interaction process holds promise for quantum control in the field of photonics.

DOI: 10.1063/5.0257482

The permittivity tensor of gold nanofilms of different orientations and thicknesses in the frequency range of 0-6 eV is theoretically studied, revealing significant differences from the bulk gold permittivity. Two models are proposed to calculate the longitudinal ɛ‖(h, ω) and transverse ɛ⊥(h, ω) parts of the permittivity tensor in the specified frequency range for gold nanofilms of different thicknesses and surface orientations (001), (110), and (111). These models explain intense peaks in the real and imaginary parts of permittivity at 0-2 eV. The model for calculating the transverse permittivity does not use the Drude model but uses the interband contribution of the bulk material determined through DFT calculations and the contribution of electron motion perpendicular to the nanoslab surface. This contribution takes into account the electron motion inside an infinitely deep one-dimensional potential well with a set of discrete electron levels and makes it possible to calculate the imaginary part of the permittivity using Fermi's golden rule. The model for calculating the longitudinal permittivity employs an interpolation scheme using the tabulated permittivity of bulk gold and that of several plates with different thicknesses. The difference between experimental permittivity values and those calculated using DFT and the proposed models is discussed. The proposed algorithms enabled a Python program for fast calculation of ɛ⊥(h, ω) and ɛ‖(h, ω) of gold nanofilms of any thickness and above-mentioned orientations in the 0-6 eV range without computationally expensive DFT calculations. This program is included in the supplementary material. The proposed approaches can be easily applied to nanofilms made of other metals.

https://doi.org/10.1016/j.vacuum.2025.114452

The authors regret the omission of supplementary information file in the aforementioned article. We hereby add the missing text file describing the experiment and calculation details.