Новые публикации
The Excitation of Surface Plasmon-Polaritons in the Process of Raman Interaction
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.
Fast calculation of the permittivities of gold thin films in the frequency range of 0-6 eV
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.
Coexistence of gapless and gapped vortex modes with Majorana corner states in a two-dimensional second-order topological superconductor
Physical Review B, 111(21), art. no. 214507
Corrigendum to “High-vacuum carbosilicothermic reduction of manganese in thin films
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.
Hybridization of the Acoustic Tamm States and Defect Modes of a One-Dimensional Phononic Crystal
https://doi.org/10.1134/S1062873825710906
The spectral properties of a one-dimensional phononic crystal bounded by a reflector in the form of an air layer are studied. A defect in a phononic crystal with a reflector at the edge results in coupling between the detect mode and acoustic Tamm state. This coupling between modes of different natures manifests as the hybridization of modes, and the repulsion of dips in the reflectance spectrum is explained by avoided crossing of the modes.
Néel temperature of a quasi-two-dimensional triangular-lattice antiferromagnet
https://doi.org/10.1134/S0040577925050083
Based on the atomic representation for spin operators in the case of an arbitrary value of the spin �, we study the influence of quantum fluctuations on spin-wave renormalizations of the Néel temperature �N and on the magnetization of quasi-two-dimensional triangular-lattice antiferromagnet sublattices. The application of combined Green’s functions constructed using spin operators and their partial components allows easily obtaining a closed system of equations determining not only all branches of the spectrum of collective excitations but also the occupation numbers of states of an atom with different values of the spin projection. We show that the renormalization of �N is expressed in terms of the generalized Watson integral. Its nontrivial dependence on the degree of quasi-two-dimensionality and on the dynamical properties of three spectral branches determines the behavior of the critical temperature in the cases of different relations between the parameters of the quasi-two-dimensional antiferromagnet.
Spin-Glass Transition in Mn0.75Co2.25BO5 Compound
https://doi.org/10.26907/mrsej-24301
Temperature-dependence measurements specific heat, thermoelectric power, conductivity, and electron paramagnetic resonance measurements were performed on Mn0.75Co2.25BO5 powder at temperatures above 290 K. Single crystals of Mn0.75Co2.25BO5 were grown by the flux method using Bi2Mo3O12-based solvent diluted with Na2CO3. To investigate EPR and specific heat capacity, the single crystals were ground to powder. The temperature dependencies of the resistance, specific heat, Seebeck constant, and EPR spectra in the range from 290K to 700K were obtained. The transition from the dielectric state to the semiconductor state was detected at 348 K, consistent with the change in the fine structure of the EPR spectrum associated with S = 5/2 for the manganese ion Mn2+.
Far-red emitting phosphors for plant growth applications: fitted and enhanced via cation substitution of Gd3+
https://doi.org/10.1039/D5TC00678C
Far-red (FR) light is involved in plant photomorphogenesis as a light signal. To realize the match between the absorption peak (730 nm) of a plant photosensitive pigment (Pfr) and the emission spectrum (708 nm) of a Y3Ga4.87O12:0.13Cr3+ (YGO:0.13Cr3+) phosphor, in this study, we employed an ‘A site modification-B site response’ crystal-field-modulation strategy using the garnet structure Y3Ga5O12, where doping large radius Gd3+ at the A site induced [YO8] polyhedral expansion and triggered [GaO6] octahedral distortion, thereby weakening the crystal field strength to achieve a red shift in the spectrum. The optimized Gd1.2Y1.8Ga4.87O12:0.13Cr3+ (GYGO:0.13Cr3+) phosphor exhibited high external quantum efficiency (34%) and excellent thermal stability (85.5% intensity at 423 K) under 450 nm excitation. Its emission peak at 726 nm was significantly close to 730 nm, while its luminescence intensity was improved by 141% that of the original system. It was successfully fabricated as an FR pc-LED device, achieving a 36.86 mW output power and 13.5% photoelectric efficiency at 100 mA current. Lettuce growth experiments showed that the device enhanced biomass production by 30% through precise spectral adaptation. The present work can promote the leap in plant lighting from rough supplementation to spectral customization through the whole chain of structural aberration–photoelectricity–biological effects.
Electron-phonon coupling in EuAl4 under hydrostatic pressure
DOI: https://doi.org/10.1103/PhysRevB.111.195150
In the intermetallic rare-earth tetragonal EuAl4 system, competing itinerant exchange mechanisms lead to a complex magnetic phase diagram, featuring a centrosymmetric skyrmion lattice. Previous inelastic x-ray scattering (IXS) experiments revealed that the incommensurate charge-density wave (CDW) transition in EuAl4 (𝑇CDW=142K) is driven by momentum-dependent electron-phonon coupling (EPC). We present the results of IXS under high hydrostatic pressure induced by diamond anvils and show how the EPC in EuAl4 is renormalized and suppressed in the material's temperature-pressure phase diagram. Our findings highlight the crucial role of momentum-dependent EPC in the formation of the CDW in EuAl4 and provide further insights into how external pressure can be used to tune charge ordering in quantum materials.
Cerium(III) bromide hybrid with near-unity photoluminescence quantum efficiency for high-resolution and fast x-ray imaging
https://doi.org/10.1016/j.fmre.2025.02.007
Trivalent lanthanide Ce(III) with a typical allowed 4f – 5d transition generally exhibits short decay time in a nanosecond level, beneficial to fast X-ray imaging applications. Herein, we rationally design and synthesize two zero-dimensional Ce3+ based halide hybrids, namely [Emim]3CeBr6 and [Emmim]3CeBr6 (Emim = 1-ethyl-3-methylimidazolium; Emmim = 1-ethyl-2,3-dimethylimidazolium), both exhibiting intense broad-band violet-to-blue emission originated from Ce3+ with near-unity photoluminescence quantum yield. The short nanosecond decay time and the heavy atom effect further inspire us to explore their X-ray scintillation performance. Up to 48,000 photons MeV-1 light yield is derived together with the low detection limit (around 626 nGy s-1), and thus a composite film is fabricated to achieve dynamic fast X-ray imaging. This study enlarges the family of scintillators in Ce(III)-based halide hybrid with short decay time.
Luminescence enhancement effects of CaxSr2‒xNb2O7:Er3+,Tm3+ phosphors for temperature sensing and anti-counterfeiting applications
https://doi.org/10.1016/j.jre.2024.06.022
Er3+- and Tm3+-doped CaxSr2‒xNb2O7 (CxS2‒xN, x = 0.6, 0.8, 1.0, 1.2, 1.4) phosphors with layered perovskite structure were designed. These phosphors exhibit a dominant emission peak at 549 nm under 980 nm laser excitation, attributed to the 4S3/2 → 4I15/2 transition. By increasing the content of Ca2+, the crystal field regulation of rare earth ions is realized and the luminescence enhancement is induced, which is manifested by the increase of 2H11/2,4S3/2 → 4I15/2 emission. Furthermore, the temperature sensing sensitivities of C0.6S1.4N:Er,Tm and C0.6S1.4N:Er,Tm based on non-thermally coupled energy levels were studied. Finally, an anti-counterfeiting imprint was prepared using phosphors, which have high brightness and excellent photothermal stability. This work not only confirms that closer ionic radii substitution enables to increase the electronic density of states, improve the crystal field symmetry and enhance the luminescence, but also provides a promising phosphor system for temperature sensing and anti-counterfeiting applications, opening up new prospects in the optimization of the optical properties of phosphors.
Highly efficient Fe3+-activated hexaaluminate phosphor with multisite luminescence and high thermal stability toward plant lighting
https://doi.org/10.1016/j.jallcom.2025.181052
Fe3+ activator is a NIR candidate due to its non-toxicity and low cost. Herein, a NIR phosphor BaZnAl10O17: Fe3+ (BZA: Fe3+) with high external quantum efficiency (EQE = 54.1 %) and excellent thermal stability is synthesized. Various emission spectra can be observed under three different excitation wavelengths, which is attributed to the occupation of Fe3+ on two octahedral sites and a tetrahedral site. The anti-thermal quenching phenomenon under the excitation wavelength of 340 nm can be attributed to trap-assisted energy compensation, weak electron-phonon coupling and energy transfer between different Fe3+ sites. These sparkling properties indicate application potential in the field of plant lighting.
High-vacuum carbosilicothermic reduction of manganese in thin films
https://doi.org/10.1016/j.vacuum.2025.114398
High-vacuum carbosilicothermic reduction of MnOx thin films on Si(100) substrates was investigated in the temperature range of 200–700 °C using in-situ Auger electron spectroscopy along with mass spectroscopy and ex-situ X-ray photoelectron spectroscopy. Carbothermic reduction of manganese, accompanied by the CO evolution, occurs over the entire temperature range. When heated above 500 °C, silicothermic reduction and formation of manganese silicides are observed. The efficiency of carbothermic reduction of Mn in thin films turned out to be higher at C:Mn = 1:10 than at C:Mn = 1:5. Carbon in the samples is assumed to be present in two forms: as amorphous carbon in a mixture with oxygen and manganese, and as individual, larger particles with a graphite structure. The particle size depends on the power of the magnetron source and influences the carbon coalescence activity, which competes with the carbothermic reduction process. The efficiency of silicothermic reduction on the film surface depends on the initial carbon concentration.
Transformation of f-f absorption bands of holmium ions in Ho0.75Nd0.25Fe3(BO3)4 crystal during spin-reorientation transition
https://doi.org/10.1016/j.optmat.2025.117150
Polarized absorption spectra of the Ho0.75Nd0.25Fe3(BO3)4 crystal in the region of 5I8→5F5, 5S2 + 5F4, 5F3 and 5F2 absorption bands of Ho ions were studied as a function of temperature in the range of 5–20 K. The absorption spectra were decomposed into Lorentzian or Gaussian components. Below 203 K, the local symmetry of the holmium ion is C2. However, an analysis of the polarization of the absorption lines from the point of view of the selection rules showed that in the easy-axis state of the crystal (T < TR = 6.9 K), the local symmetry of the holmium ion is close to D3. At T > TR, a distortion of the local symmetry appears, which increases with increasing temperature. Shifts in the positions of absorption lines are observed at the spin-reorientation transition. The shifts are different for different lines. This means that the local magnetic anisotropy of the holmium ion, the Ho–Fe exchange energy, and the local crystal field are different in different excited states of holmium. Significant and different changes in the intensity of absorption lines depending on temperature were observed both during the reorientation transition and above it, which is a consequence of changes of the local crystal field in excited states with temperature.
Study of phase transitions in α-Fe2O3 during mechanical grinding in a high-energy ball mill
https://doi.org/10.1007/s11182-025-03448-6
The phase transformations, taking place in α−Fe2O3 during its mechanical grinding in an AGO-2C planetary ball mill with an aim to manufacture a Fe3O4-based magnetic powder, are studied. The grinding is performed using steel vials and balls under different modes, grinding times (up to 120 min), mill rotation frequencies (1290, 1820, 2220 rpm), processing media (water, isopropyl alcohol, dry grinding in air), degree of filling vials with balls and powder (from 1/12 to 2/3 of vial volume), and ball-to-powder mass ratios (from 2.5:1 to 20:1). It is shown that different grinding modes strongly affect the−Fe2O3→Fe3O4 phase transition, resulting in different phase concentration ratios in the milled powder. It is noted that the magnetite concentration increases with the grinding energy density, which depends on the rotation frequency and grinding time. The most effective modes of the Fe3O4-based nanostructured powder manufacture are established, which involve the maximum rotation frequency, the grinding time up to 120 min, and the ball-to-powder ratio 10:1. The magnetic powder thus produced has the Curie temperature of 556 °C and the saturation magnetization of 65 emu/g.
Monitoring forest plant moisture using L1-band navigation satellite signals
Cyclic superelasticity behavior of Co35Ni35Al28Fe2 single crystals
https://doi.org/10.1016/j.matlet.2025.138728
The effect of cyclic loading/unloading on high-temperature superelasticity and the (B2 + γ/γ’)-microstructure was studied in quenched Co35Ni35Al28Fe2 single crystals oriented along the [001]B2-direction. They displayed excellent superelastic response in compression over 100 loading/unloading cycles at 423 K. This superelasticity response is attributed to the high-strength crystallographic [001]B2 orientation of the B2-matrix and strengthening of the γ-phase due to nanosized γ’-particles. The stress-induced B2-L10 martensitic transformation during loading/unloading cycles was accompanied by plastic deformation via twinning of the secondary γ/γ’-phase and dislocation accumulations in B2-matrix around the γ/γ’-phase. This results in a reduction in the critical stress for the martensite formation, stress hysteresis and reversible strain during cycling.
Time-dependent DFT-based study of bacteriochlorophyll a optical properties within the B800 part of LH2 Rhodoblastus acidophilus light-harvesting complex
https://doi.org/10.48550/arXiv.2503.03246
We use time-dependent density functional theory-based approaches, TD-DFT and TD-DFTB, to investigate the optical absorption of B800 part of Rhodoblastus acidophilus light-harvesting complex 2 (LH2). Both methods are shown to give qualitative agreement with experimental spectra for a single BChl a molecule and for the optimized structure of B800 complex containing nine of such molecules. We proved the absence of any sizable effects originating from the interaction between adjacent molecules, thus optical features of B800 LH2 part should not be attributed to the structural organization of pigments. In addition, time-dependent procedure itself was found to be crucial for the correct description of BChl a absorption spectrum.
Oblique Incidence of an Electromagnetic Wave on a Plane-Parallel Dielectric Plate
https://doi.org/10.1134/S1063784225700057
Using electrodynamic analysis of the 3D model of a plane-parallel ideal dielectric plate, the propagation of plane linearly polarized electromagnetic waves is investigated in the case when their angle of incidence φ deviates from the normal to the plane of the plate. It is found that in the case of parallel polarization, when the electric field vector lies in the plane of incidence and magnetic field vector is parallel to the plane of plate, the Q factor of the observed half-wave resonance first decreases to its minimal value with increasing φ as the Brewster angle is approached, and then increases, tending to infinity as φ → 90°. In the case of perpendicular polarization, when the magnetic field vector lies in the plane of incidence and the electric field vector is parallel to the plane of the plate, the Q factor of the half-wave resonance gradually increases with increasing φ, also tending to infinity as φ → 90°. However, the dependences of the observed monotonic increase in the resonance frequencies with the angle of incidence are identical for both polarizations. The results of experiment with a plane-parallel plate made of ultrahigh molecular weight polyethylene with a dielectric constant of 2.5, which has been performed using broadband horn antennas, are in good agreement with the results of the electrodynamic calculation based on the 3D model.
Synthesis of MoSSe and WSSe via direct ampule method: Exploring structural and electronic properties, liquid exfoliation and electrocatalytic performance for hydrogen production
https://doi.org/10.1016/j.jallcom.2025.180642
Since catalytically active materials require special synthesis conditions, which cause difficulty in scaling, it is necessary to develop new lightweight scalable approaches for industrial applications. The most obvious way is to use elementary components to fabricate complex structures. In our work, we used a fundamental ampoule synthesis method to produce MSSe (M = Mo, W) powders with a homogeneous random distribution of chalcogen atoms. The synthesized samples exhibit P63/mmc space group indicating the existence of 2 H phase which was proved by comprehensive experimental and theoretical analysis and demonstrates rational characteristics in the hydrogen evolution reaction. The Tafel slopes for synthesized MoSSe and WSSe are 93 and 86 mV/dec, respectively. Moreover, the MSSe samples demonstrate the same catalytic activity in the hydrogen evolution reaction as the samples subjected to ultrasonic treatment in N-Methyl-2-pyrrolidone, with Tafel slopes of 92 and 88 mV/dec for MoSSe and WSSe, respectively.
Photocontrolled chiral-nematic Fabry-Pérot cavity
https://doi.org/10.1016/j.optlastec.2025.113012
The spectral and polarisation characteristics of a Fabry–Pérot cavity filled with photo-controlled chiral nematic are investigated. The chiral nematic under planar-tangential boundary conditions is used, enabling the structure to change in the twist angle continuously under the action of the controlling blue or UV light. An increase in the structure twist angle leads to a rise in the geometric phase of the eigenmodes accompanied by a red spectral shift of ��-modes and a blue spectral shift of ��-modes. The spectral shift of the modes is studied experimentally, through numerical simulation and by analytical treatment. A generalised resonance diagram of the chiral nematic cavity is obtained. Measurements of the geometric phase values as a function of the structure twist angle are made. The proposed chiral nematic cavity with a variable geometric phase can be promising to develop photonic devices with photo-controlled features.
Structures and Morphologies Attained by Spinel Nano-Ferrites
Ferrites are a type of magnetic oxide that have garnered a lot of attention due to their versatile properties and numerous applications in various technological domains. The morphological and structural aspects of ferrites are explained in this chapter, with special attention to the finer points of their crystallography and surface features. The atomic and nanoscale structural configurations that are inherent to matter through analytical techniques such as spectroscopy, electron microscopy, and X-ray diffraction (XRD) are discussed. The first section of the chapter examines the crystallography of ferrites, outlining their different crystal forms and phases, including the ubiquitous spinel structure and hexagonal phases. Extensive investigation of XRD patterns provide insight into lattice properties, crystal symmetry, and phase purity. Techniques including transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM) used to examine the surface characteristics, particle size distribution, and agglomeration tendencies are described. We also discuss how the synthesis setting affects the morphological features, which sheds light on the specifics of ferrite creation. In addition to catalysis, the chapter also demonstrates the role of ferrite morphology in a range of applications, including electronics, biomedical, and environmental remediation. The relationship between structural-morphological properties offers insights that could help improve the development and application of ferrite-based materials. The knowledge gained from this chapter should spur advancements in the design, production, and application of ferrite in numerous industries, resulting in advances in electronics, magnetic materials, catalysis, and other domains.
Orientation order and polarizability density of oligofluorene molecules F(Pr)5F(MB)2 in glassy nematic phase
Scattering matrix method for anisotropic layered systems
https://doi.org/10.1364/JOSAA.546862
The scattering problem for anisotropic layered systems is solved by modification of Rumpf’s scattering matrix method [Prog. Electromagn. Res B 35, 241 (2011)
Crossref ; “Computational electromagnetics. Topic 2” (2024)]. The modified method allows one to calculate the scattering coefficients as well as the electromagnetic field distribution along the layered structure. The method is verified in application to the scattering problem for a cholesteric liquid crystal layer, a magneto-optic structure, a photonic crystal covered by metal, and a slab made of left-handed material.
Thermodynamics of s ± -to- s + + transition in iron pnictides in the vicinity of the Born limit
To study the thermodynamic properties of the disorder-induced transition between �± and �++ superconducting gap functions, we calculate the grand thermodynamic potential Ω in the normal and the superconducting states. An expression for the difference between the two, ΔΩ, is derived for a two-band model for Fe-based systems with nonmagnetic impurities. The disorder is considered in a �-matrix approximation within the multiband Eliashberg theory. In the vicinity of the Born limit near the �±-to-�++ transition, we find two solutions obtained for opposite directions of the system's evolution with respect to the impurity scattering rate. By calculating the change in entropy ΔS and the change in the electronic specific heat ΔC from ΔΩ, we show that such a hysteresis is not due to the time-reversal symmetry breaking state, but that it instead points to the first order phase transition (PT) induced by the nonmagnetic disorder. Based on the ΔΩ calculations, a phase diagram is plotted representing the energetically favorable �± and �++ states and the transition between them. At finite temperature, a first order PT line there is limited by a critical end point. Above that point, the sharp �±→�++ transition transforms into a crossover between �± and �++ states.
Investigation of drug release kinetics from biodegradable polyhydroxyalkanoate microparticles
https://doi.org/10.1007/s11144-025-02852-w
In this work, spray-dried poly(3-hydroxybutyrate-co-3-hydroxyvalerate) microparticles (P(3HB-co-3HV) MPs) containing conventional antibacterial drug rifampicin (RIF), as well as novel cytostatic ozonide (OZ) were obtained and characterized. The effect of drug chemical structure on its encapsulation and release profile, as well as MPs characteristics (mean size, polydispersity index, zeta potential) was investigated. The obtained RIF-MPs and OZ-MPs revealed the mean diameter of 3.14 ± 0.08 μm and 1.94 ± 0.05 μm, respectively, spherical shape, smooth surface and uniform size distribution. The release of RIF and OZ from the P(3HB-co-3HV) microparticulate matrix had a two-stage pattern with the burst effect and followed the Fickian diffusion-controlled mechanism.
Negative thermal expansion effects, spectroscopic properties and electronic structure transformations in Tm2Zr(MoO4)5
https://doi.org/10.1016/j.materresbull.2025.113485
New noncentrosymmetric molybdate Tm2Zr(MoO4)5 was synthesized. The crystal structure variation with temperature was determined by Rietveld analysis. At 303 K, the monoclinic structure was determined in space group P21. A reversible phase transition P21↔Cmc21 was found at 390 K. From 423 to 520 K, nearly a ZTE (α = 0.7 × 10−6 K−1) behavior was revealed. In the range of 520–720 K, the negative thermal expansion (NTE) effect (α = -2.3 × 10−6 K−1) is evident for the cell volume. Tm2Zr(MoO4)5 is stable up to 1100 K. Electronic structures of monoclinic and orthorhombic Tm2Zr(MoO4)5 were evaluated by DFT methods. The bandgap values determined for monoclinic Tm2Zr(MoO4)5 are Eg direct = 3.83 eV and Eg indirect = 3.43 eV. The vibrational properties of monoclinic phase were characterized by Raman spectroscopy. The photoluminescence emission in monoclinic Tm2Zr(MoO4)5 at 303 K is dominated by a narrower band at 650 nm due to the 1G4 - 3F4 transition.
Achieving improved dielectric energy storage properties in Na0.4505Bi0.3825Sr0.136Nb0.085Er0.015TiO3 ferroelectric ceramics via La modification and processing optimization
https://doi.org/10.1016/j.ceramint.2025.04.041
In this study, lanthanum (La) modified 0.85(0.9Na0.5Bi0.5TiO3–0.1Na0.8Sr0.1NbO3) −0.15Sr0.85Er0.1TiO3 ceramics, abbreviated as (NBT–NSN)–SET–xLa, ceramics were synthesised. The best 0.020 La ceramic specimens were selected and improved by viscous polymer processing (VPP) to further enhance their energy storage densities. It ultimately reached a high breakdown field strength of 460 kV/cm, at which the recoverable energy density and efficiency of 6.87 J/cm3 and 74.7 % were attained. At present, although many studies on La doping have shown that La elements can effectively refine grains, thereby increasing electrical breakdown strength and ultimately improving energy storage performance. However, there is no clear explanation at the mechanism layer. In this article we try to make this clearer in terms of structural evolution and modelling. We use XRD and Raman spectroscopy to elucidate the effect of La doping on structural evolution and explain the relationship between structure and properties. In addition, this study combined with comsol software to simulate the electrical breakdown process after La doping, which can help readers to fully understand the mechanism and lay a theoretical foundation for future industrial applications.
Study of the dependence of hydroxyl groups numbers on treatment time during the synthesis of fullerenols
https://doi.org/10.1080/1536383X.2025.2485241
Our present study aims to obtain and examine the fullerenols (water-soluble derivatives of fullerenes) with various amounts of hydroxyl groups. The work presents the results of obtaining fullerenols by boiling in nitric acid with subsequent hydrolysis of polynitro intermediates with water at different treatment durations. The obtained samples were certified by X-ray photoelectron and IR spectroscopy methods and it was found that 10-h treatment allowed obtaining fullerenol with the composition C60Ox(OH)y, where x + y = 12−14, 15-h treatment yielded C60Ox(OH)y, where x + y = 16−18, and 20-h boiling in acid yielded C60Ox(OH)y, where x + y = 24−26. The reproducibility of the obtained results allowed the addition of a predictable number of functional groups.
Dependence of the energy and orbital structure of local states in CuO monolayer on Coulomb parameters
https://doi.org/10.48550/arXiv.2502.01483
The dependence of the energies and orbital structure of local states in the CuO monolayer on intra- and interatomic Coulomb interactions on copper and oxygen orbitals is studied. The electronic system is described within the eight-band p-d model in the hole representation with the on-site energies and hopping integrals obtained using density functional theory. CuO cluster multiparticle eigenstates are calculated using exact diagonalization. The difference between the energy dependencies on the Coulomb parameters for the states with the predominant probability density on the d-orbital and the states in which hole occupies p-orbitals leads to crossover of d- and p-states. The ground single-hole and two-hole states which determine the electronic structure of the low-energy excitations have the character of d- or p-orbitals in the different regions of the Coulomb parameters space. The gap between the energies of the dispersionless quasiparticles forming the top of the valence band and conductivity band also have different values in these two regions. The magnitude of this gap and the orbital character of the local multiparticle states change sharply even with an insignificant change in the Coulomb interactions within the boundary region of parameters between the regions in which the local states are formed by the d- or p-orbitals.
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