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This study explores cobalt–cerium (Co90Ce10) thin films deposited on silicon (Si) (100) and glass substrates via direct current (DC) magnetron sputtering, with thicknesses from 10 nanometer (nm) to 50 nm. Post-deposition annealing treatments, conducted from 100 °C to 300 °C, resulted in significant changes in surface roughness, surface energy, and magnetic domain size, demonstrating the potential to tune magnetic properties via thermal processing. The films exhibited hydrophilic behavior, with thinner films showing a stronger substrate effect, crucial for surface engineering in device fabrication. Increased film thickness reduced transmittance due to photon signal inhibition and light scattering, important for optimizing optical devices. Furthermore, the reduction in sheet resistance and resistivity with increasing thickness and heat treatment highlights the significance of these parameters in optimizing the electrical properties for practical applications. [ABSTRACT FROM AUTHOR]

Ripples on graphene play a crucial role in manipulating its physical and chemical properties. However, producing ripples, especially at the nanoscale, remains challenging with current experimental methods. In this study, we report that tiny ripples in graphene can be generated by the adsorption of a single metal cation (Na+, K+, Mg2+, Ca2+, Cu2+, Fe3+) onto a graphene sheet, based on the density functional theory calculations. We attribute this to the cation–π interaction between the metal cation and the aromatic rings on the graphene surface, which makes the carbon atoms closer to metal ions, causing deformation of the graphene sheet, especially in the out-of-plane direction, thereby creating ripples. The equivalent pressures applied to graphene sheets in out-of-plane direction, generated by metal cation–π interactions, reach magnitudes on the order of gigapascals (GPa). More importantly, the electronic and mechanical properties of graphene sheets are modified by the adsorption of various metal cations, resulting in opened bandgaps and enhanced rigidity characterized by a higher elastic modulus. These findings show great potential for applications for producing ripples at the nanoscale in graphene through the regulation of metal cation adsorption. [ABSTRACT FROM AUTHOR]

The effects of different Mn concentrations on the generalized stacking fault energies (GSFE) and elastic properties of MnxCoCrFeNi high-entropy alloys (HEAs) have been studied via first-principles, which are based on density functional theory. The relationship of different Mn concentrations with the chemical bond and surface activity of MnxCoCrFeNi HEAs are discussed from the perspectives of electronic structure and work function. The results show that the plastic deformation of MnxCoCrFeNi HEAs can be controlled via dislocation-mediated slip. But with the increase in Mn concentration, mechanical micro twinning can still be formed. The deformation resistance, shear resistance, and stiffness of MnxCoCrFeNi HEAs increase with the enhancement of Mn content. Accordingly, in the case of increased Mn concentration, the weakening of atomic bonds in MnxCoCrFeNi HEAs leads to the increase in alloy instability, which improves the possibility of dislocation. [ABSTRACT FROM AUTHOR]

The substitutional doping of nitrogen is an efficient way to modulate the electronic properties of graphene and carbon nanotubes (CNTs). Therefore, it could enhance their physical and chemical properties as well as offer potential applications. This paper provides an overview of the experimental and theoretical investigations regarding nitrogen-doped graphene and CNTs. The formation of various nitrogen defects in nitrogen-doped graphene and CNTs, which are identified by several observations, is reviewed. The electronic properties and transport characteristics for nitrogen-doped graphene and CNTs are also reviewed for the development of high-performance electronic device applications. [ABSTRACT FROM AUTHOR]

Recently, bulk Mg3X2 (X=As, Sb) have been intensively studied for their unique properties for thermoelectric use. However, studies on their two-dimensional counterparts are not sufficient. In this work, we systematically investigated the electronic, mechanical, vibrational, and piezoelectric properties of Mg3X2 (X = As, Sb) monolayers. The results indicate that both monolayers have negative formation energies with dynamical and mechanical stability. Mg3As2 monolayer is a narrow band gap semiconductor, while Mg3Sb2 monolayer is an indirect one. The origin of the band structure was revealed by the calculated partial density of states. The bonding property of both monolayers was analyzed by different methods. Elastic constants were obtained by density functional perturbation theory, and the related physical quantities were derived and analyzed. In-plane strengths along the zigzag and armchair directions of both materials were calculated, and the fracture mechanisms were uncovered. The vibrational modes at the Brillouin center were classified through group theory analysis, and the corresponding eigenvectors and frequencies were calculated and presented. Infrared vibrational spectra were simulated, and the reason for the vanishment of some infrared peaks was disclosed. Piezoelectric and dielectric coefficients were also computed and discussed. [ABSTRACT FROM AUTHOR]

This paper systematically investigates the structure, stability, and electronic properties of niobium carbide clusters, NbmCn (m = 5, 6; n = 1–7), using density functional theory. Nb5C2 and Nb5C6 possess higher dissociation energies and second-order difference energies, indicating that they have higher thermodynamic stability. Moreover, ab initio molecular dynamics (AIMD) simulations are used to demonstrate the thermal stability of these structures. The analysis of the density of states indicates that the molecular orbitals of NbmCn (m = 5, 6; n = 1–7) are primarily contributed by niobium atoms, with carbon atoms having a smaller contribution. The composition of the frontier molecular orbitals reveals that niobium atoms contribute approximately 73.1% to 99.8% to NbmCn clusters, while carbon atoms contribute about 0.2% to 26.9%. [ABSTRACT FROM AUTHOR]

Double traditional metal (TM) Janus MXenes have more superior properties when compared with MXenes. The electronic and optical properties, Bader charge and quantum capacitance of ZrMCO 2 (M = Sc, Ti, V, Cr, Mn, Fe, Y, Zr, Nb, Mo, Hf, Ta, W) are explored by density functional theory (DFT). The stability of these systems is confirmed by cohesive energy. The substitution of Ti/Hf atoms results in the decrease of bandgap of ZrTiCO 2 /ZrHfCO 2 , which is induced by the redshift of conduction band minimum (CBM). ZrMCO 2 (M = Cr, Mn) are magnetic semiconductors and ZrMCO 2 (M = Sc, V, Y, Fe) are magnetic metals. All doping atoms except Hf improve the maximum quantum capacitance of ZrMCO 2 at positive bias. Wide voltage makes ZrMCO 2 (M = Nb, Ta, W) change into anode material and ZrFeCO 2 into cathode material. ZrMCO 2 (M = Sc, Mn, Y, Hf, Zr) and ZrMCO 2 (M = V, Cr) can serve as cathode and anode materials in whole voltage, respectively. Much charge accumulating between Fe and C atoms results in the smallest Fe–C bond among all M − C bonds, which indicates the strongest interaction between Fe and C atoms. Optical properties and work function are further explored. [ABSTRACT FROM AUTHOR]

CoxBy alloy with high hardness and high melting point has wide range of applications in many fields because of its stable chemical property, high strength, and good thermal stability. In this work, the thermodynamic and electrical properties of five CoxBy alloys (CoB, Co2B, Co3B, Co23B6 and Co5B16), were studied and compared based on a first-principles approach. The elastic constant and related mechanical property of the binary alloys were calculated by using the energy-strain method, and the thermodynamic properties such as the Debye temperature (ΘD) and the coefficient of thermal expansion (α) within a finite temperature were calculated based on the quasi-simple harmonic Debye model. By comparing the mechanical parameters of the binary alloys, it is found that the comprehensive mechanical property of the CoB alloy is the best among the studied alloys; the state density mapping indicates that all five CoxB y alloys have good metallicity and electrical conductivity, and have some potential applications in the field of electrode materials. In Co3B and Co23B6 alloys, there is a resonance peak between the d electron orbital of Co atom and the p electron orbital of B atom, indicating that there is a significant chemical bond between Co—B.The study complements the gap of thermomechanical property parameters of CoxBy binary alloys and provides a theoretical reference for the design and application of Co based or Co—B binary alloy materials.

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Using first-principles calculations, the structural, electronic, piezoelectric, and optical properties of Janus Sc2CXY (X ≠ Y, X/Y = F, Cl, Br, and I) MXenes were comprehensively investigated. All of the studied MXenes are structurally stable. Both Young's modulus Y and Poisson's ratio ν are isotropic and can be modulated by the surface-functionalized halogen atoms. In addition, the band gaps of all the Janus Sc2CXY MXenes can be modulated from 0.638 eV to 1.437 eV by different functional groups. Interestingly, the semiconductor–metal transition for Janus Sc2CXI (X = F, Cl, and Br) can occur when the compressive strain reaches 6%. Furthermore, because of their symmetric breaking, the Janus Sc2CXY MXenes exhibit excellent in-plane and out-of-plane piezoelectric properties. High optical absorption is found in the visible and ultraviolet ranges for all the studied MXenes, and it is expected that they can be utilized in the fields of piezoelectric and optoelectronic nanodevices. [ABSTRACT FROM AUTHOR]

First principles calculations based on density functional theory (DFT) were performed to investigate the structural, electronic, optical and mechanical properties of pristine GaAs compound and its alloy; Ga0.75Al0.25As, Ga0.75In0.25As, Ga0.75Sn0.25As, Ga0.75Ti0.25As. WIEN2K and Quantum expresso (QE) codes were adopted for calculations using generalized gradient approximation (GGA) in Perdew-Burke Erzenhoff (PBE) as exchange correlation function for both codes. Full potential linear augmented plane wave (FPLAPW) with the local orbital method was adopted as implement in WIEN2K code. In QE code, norm-conserving pseudopotentials were employed on a plane-wave expansion of the wave functions. Structural and electronic properties were elaborated since their result gives information about the optical and mechanical performance. Electronic band structure and optical parameters were performed using WIEN2K code. Underestimation of band gap observed from DFT calculations were corrected by using Modified Becke and Johnson (mBJ). Mechanical components were determined using QE with thermo_pw package. Lattice constant, volume, bulk modulus and other physical parameters were calculated for structural properties. Discrepancy in these parameters as observed in crystal structure is associated to difference in ionic radius of host and substituted atom. The results of band structure and density of states were calculated for electronic properties. All the studied compounds were semiconductors in nature except Ga0.75Sn0.25As which displayed metallic character. Optical parameters including extinction coefficient, absorption coefficient, refractive index, optical conductivity, optical reflectivity and energy loss function have been computed from the dielectric function at energy range of 0 to 25 eV using the Kramers-Kronig transformations. Calculated elastic function were used to compute the mechanical properties such as anisotropic, brittle characteristics, stiffness and many others. All the results were compared with available theoretical and experimental records.

Ripples on graphene play a crucial role in manipulating its physical and chemical properties. However, producing ripples, especially at the nanoscale, remains challenging with current experimental methods. In this study, we report that tiny ripples in graphene can be generated by the adsorption of a single metal cation (Na+, K+, Mg2+, Ca2+, Cu2+, Fe3+) onto a graphene sheet, based on the density functional theory calculations. We attribute this to the cation–π interaction between the metal cation and the aromatic rings on the graphene surface, which makes the carbon atoms closer to metal ions, causing deformation of the graphene sheet, especially in the out-of-plane direction, thereby creating ripples. The equivalent pressures applied to graphene sheets in out-of-plane direction, generated by metal cation–π interactions, reach magnitudes on the order of gigapascals (GPa). More importantly, the electronic and mechanical properties of graphene sheets are modified by the adsorption of various metal cations, resulting in opened bandgaps and enhanced rigidity characterized by a higher elastic modulus. These findings show great potential for applications for producing ripples at the nanoscale in graphene through the regulation of metal cation adsorption.

The substitutional doping of nitrogen is an efficient way to modulate the electronic properties of graphene and carbon nanotubes (CNTs). Therefore, it could enhance their physical and chemical properties as well as offer potential applications. This paper provides an overview of the experimental and theoretical investigations regarding nitrogen-doped graphene and CNTs. The formation of various nitrogen defects in nitrogen-doped graphene and CNTs, which are identified by several observations, is reviewed. The electronic properties and transport characteristics for nitrogen-doped graphene and CNTs are also reviewed for the development of high-performance electronic device applications.

Abstract Various doping concentrations of boron (B)-doped germanium nanocrystal (Ge NC) films were prepared using the plasma-enhanced chemical vapor deposition (PECVD) technique followed by thermal annealing treatment. The electronic properties of B-doped Ge NCs films combined with the microstructural characterization were investigated. It is worthwhile mentioning that the Hall mobilities $${\mu }_{\mathrm{Hall}}$$ μ Hall of Ge NCs films were enhanced after B doping and reached to the maximum of 200 cm2 V−1, which could be ascribed to the reduction in surface defects states in the B-doped films. It is also important to highlight that the temperature-dependent mobilities $${\mu }_{\mathrm{H}}(T)$$ μ H ( T ) exhibited different temperature dependence trends in the Ge NCs films before and after B doping. A comprehensive investigation was conducted to examine the distinct carrier transport properties in B-doped Ge NC films, and a detailed discussion was presented, focusing on the scattering mechanisms involved in the transport process.

Hydrogen peroxide is one of the most important commercially used oxidant and exists widely in the environment. It crystallizes in a tetragonal phase via hydrogen bond at around −0.89 °C. However, many of its fundamental properties are still not well studied. To investigate systems containing hydrogen bond, van der Waals correction must be considered. In this work, we tested a series of local and non-local van der Waals corrections within the frame of density functional theory. The optPBE-vdW and the vdW-DF-CX functionals are found to be the best ones based on the relaxed lattice parameters. Then the electronic, bonding, elastic, infrared, piezoelectric and dielectric properties are studied and discussed. The results reveal that tetragonal H2O2 is an indirect band gap insulator. Bond critical point analysis, reduced density gradient analysis and crystal orbital Hamilton population analysis uncover that the H-O···H bonds are moderate hydrogen bonds, which contribute most to the formation of the crystal. The interactions between the O atoms of neighbouring H2O2 molecules also have a bit contribution. Elastic stability of tetragonal H2O2 is confirmed and its elastic anisotropy is illustrated by directional bulk and shear moduli. The vibrational modes at the Brillouin zone center are assigned, and their frequencies and eigen-displacements are calculated. Additionally, its infrared spectrum is simulated. Its Born effective charges, piezoelectric and dielectric coefficients are also obtained and discussed.

Hydrogenated amorphous SiC (a-SiC:H) films with various Si/C ratios were prepared using the plasma-enhanced chemical vapor deposition (PECVD) technique. These films were then subjected to thermal annealing at different temperatures to induce crystallization. The electronic properties of the annealed SiC films were investigated through temperature-dependent Hall mobility measurements. It was found that the room-temperature Hall mobilities in the SiC films increased with both the annealing temperature and the Si/C ratio. This increase was attributed to the improved crystallization in the SiC films. Importantly, SiC films with different Si/C ratios annealed at different temperatures exhibited varying temperature dependence behaviors in their Hall mobilities. To understand this behavior, a detailed investigation of the transport processes in SiC films was carried out, with a particular emphasis on the grain boundary scattering mechanisms. [ABSTRACT FROM AUTHOR]

This paper systematically investigates the structure, stability, and electronic properties of niobium carbide clusters, NbmCn (m = 5, 6; n = 1–7), using density functional theory. Nb5C2 and Nb5C6 possess higher dissociation energies and second-order difference energies, indicating that they have higher thermodynamic stability. Moreover, ab initio molecular dynamics (AIMD) simulations are used to demonstrate the thermal stability of these structures. The analysis of the density of states indicates that the molecular orbitals of NbmCn (m = 5, 6; n = 1–7) are primarily contributed by niobium atoms, with carbon atoms having a smaller contribution. The composition of the frontier molecular orbitals reveals that niobium atoms contribute approximately 73.1% to 99.8% to NbmCn clusters, while carbon atoms contribute about 0.2% to 26.9%.

As the high-entropy design concept applied to the diboride ceramic system, high-entropy diboride ceramics with a wide range of composition control, is expected to become a new high-performance material for extreme high-temperature environments. Herein, the effects of four transition metal elements (Nb, Ti, Cr, W) on the phase stability and properties of (Hf, Zr, Ta)B 2 -based high-entropy diboride ceramics are systematically investigated via the first-principles calculations. All components were identified as thermodynamically, mechanically and dynamically stable from enthalpy of formation, elastic and phonon spectrum calculations. Among these, compared with the (Hf, Zr, Ta)B 2 ceramics, the addition of Nb and Ti on the metal sublattice is beneficial to improve the mechanical properties of ceramics, including Young's modulus, hardness and fracture toughness, while the introduction of Cr and W weakens the strength of covalently and ionic bonds inside the material, reducing its mechanical properties. The predicted thermophysical properties show that the high-entropy diboride ceramics containing Nb and Ti have better high-temperature comprehensive performance, including higher Debye temperature, thermal conductivity and lower thermal expansion characteristics, which is conducive to the application in extreme high-temperature environments. This research will provide important guidance for the design and development of new high-performance high-entropy diboride ceramics. [ABSTRACT FROM AUTHOR]

This research presents within the full potential linearized augmented plane wave (FP-LAPW) technique with the first-principles calculations to investigate the structural, electronic, elastic and optical properties of ternary cubic perovskites of the form TlXF3 (X= Ag and Pd) compounds. All these calculation is done by WIEN2k code within the density functional theory (DFT). The modified Becke-Johnson potential (TBmBJ) is used for the optical and electronic properties. TDOS and PDOS analysis shows that both TlAgF3 and TlPdF3 are structurally stable and the main contribution of the states in TlAgF3 compound is due to the Tl (d-orbitals) atoms and that in TlPdF3 compound, F (p-states) contributes the more. The electronic-band structure analysis shows the metallic properties having no band gaps. Optical properties are also discussed using dielectric function. Elastic calculation revealed that both compounds are anisotropic, brittle and ionic. [ABSTRACT FROM AUTHOR]

Various doping concentrations of boron (B)-doped germanium nanocrystal (Ge NC) films were prepared using the plasma-enhanced chemical vapor deposition (PECVD) technique followed by thermal annealing treatment. The electronic properties of B-doped Ge NCs films combined with the microstructural characterization were investigated. It is worthwhile mentioning that the Hall mobilities μ Hall of Ge NCs films were enhanced after B doping and reached to the maximum of 200 cm2 V−1, which could be ascribed to the reduction in surface defects states in the B-doped films. It is also important to highlight that the temperature-dependent mobilities μ H (T) exhibited different temperature dependence trends in the Ge NCs films before and after B doping. A comprehensive investigation was conducted to examine the distinct carrier transport properties in B-doped Ge NC films, and a detailed discussion was presented, focusing on the scattering mechanisms involved in the transport process. [ABSTRACT FROM AUTHOR]

The primary objective of contemporary manufacturing is to produce items that are low-cost, environmentally friendly, and energy efficient. This study aimed to investigate compounds that fulfil these criteria, with a focus on CdCrO3. The full potential linearized augmented plane wave program (FP LAPW), as in Wien2K, was employed to examine the structural, electronic, thermodynamic, and transport characteristics of the material. Structural optimization was carried out using generalized gradient approximation (GGA), with lattice constants that were deemed satisfactory based on previous theoretical and experimental results. Calculations of the magnetic characteristics of CdCrO3 show that the Cr atoms are principally responsible for magnetism. The quasi-harmonic Debye model allows for the identification of thermodynamic properties including trends, the relative Debye temperature, thermal expansion parameter, relative volume, and heat capacity at various pressures and temperatures. At constant volume, a heat capacity of 52 J/mol K was determined. The thermoelectric properties were examined using the Boltzmann transport offered by the BoltzTrap program. At room temperature, CdCrO3 had a figure of merit (ZT) value that was almost equal to one, indicating that it may be used to make thermoelectric devices with the highest possible efficiency. [ABSTRACT FROM AUTHOR]

The electronic structure of two-dimensional (2D) materials in van der Waals heterojunctions also appears extensive theoretical research, we use DFT-D2 theory to calculate the energy band, density of states, formation energy, work function, charge density difference, optical properties, and our theoretical calculations show that there is no electrons and holes redistribution at the intrinsic ZnO composite graphene interface, ZnO vacancy defects and doping not only make electron–hole good separation, but also a significant increase in the UV absorption intensity and range. We analyze the effects of the electron–hole pair separation at the heterogeneous junction interface by combining the work function and the movement of the Dirac point. We found that when defected ZnO composite graphene, there is the maximum formation energy, the value is 5.4eV,the largest moving distance of the Fermi level, 0.73eV, and the maximum absorption strength and range of UV light. This 2D van der Waals heterojunction provides a promising prospect for electrons, photovoltaic, solar cell.

The growth behavior, stability, electronic and magnetic properties of the Gd2Sin− (n = 3–12) clusters are reported, which are investigated using density functional theory calculations combined with the Saunders 'Kick' and the Artificial Bee Colony algorithm. The lowest-lying structures of Gd2Sin− (n = 3–12) are all exohedral structures with two Gd atoms face-capping the Sin frameworks. Results show that the pentagonal bipyramid (PB) shape is the basic framework for the nascent growth process of the present clusters, and forming the PB structure begins with n = 5. The Gd2Si5− is the potential magic cluster due to significantly higher average binding energies and second order difference energies, which can also be further verified by localized orbital locator and adaptive natural density partitioning methods. Moreover, the localized f-electron can be observed by natural atomic orbital analysis, implying that these electrons are not affected by the pure silicon atoms and scarcely participate in bonding. Hence, the implantation of these elements into a silicon substrate could present a potential alternative strategy for designing and synthesizing rare earth magnetic silicon-based materials. [ABSTRACT FROM AUTHOR]

Chalcogenide perovskites offer superior thermal and aqueous stability as well as a benign elemental composition compared to organic halide perovskites for optoelectronic applications. In this study, the structural, electrical, elastic, phonon dispersion, and thermodynamic features of the orthorhombic phase of chalcogenide perovskite CaZrS3 (space group Pnma) were examined by first principles calculations utilizing the plane wave pseudopotentials (PW-PPs) in generalized gradient approximations (GGA). The ground state properties such as lattice parameters, unit cell volume, bulk modulus, and its derivative were calculated and are in a good agreement with existing findings. The mechanical properties such as bulk modulus, shear modulus, Young's modulus and elastic anisotropy were calculated from the obtained elastic constants. The ratio of bulk modulus to shear modulus confirms that the orthorhombic phase of CaZrS3 is a ductile material. The absence of negative frequencies in phonon dispersion curve and the phonon density of states give an indication that the structure is dynamically stable. Finally, thermodynamic parameters such as free energy, entropy, and heat capacity were calculated with variation in temperature. The estimated findings follow the same pattern as previous efforts. [ABSTRACT FROM AUTHOR]

The electronic and optical properties of three types of aluminum phosphide bilayers are examined using density functional theory. The results indicate that they all possess proper direct gaps, which exhibit a rich variety of behaviors depending on the strain. The band gaps of these aluminum phosphide bilayers could be easily tuned in the energy range from 0 eV to 1.9 eV under a wide range of biaxial strain. Additionally, band gap transitions between direct and indirect types are found when the external strain applied on them is changed from −12% to 12%. In addition, it was found that these AlP bilayers show strong light-harvesting ability for the ultraviolet light range of the solar spectrum (400–100 nm). The results obtained here indicate that these aluminum phosphide bilayers may have significant potential applications in future nanoelectric fields. [ABSTRACT FROM AUTHOR]

The structure geometry, vibrational frequencies, electronic and optical properties of a series of donor-acceptor substituted dodecadehydrotribenzo [18] annulenes ([18] DBA) were investigated using the B3LYP method at a 6-31+G (d, p) basis set. After optimization of the structures, HOMO and LUMO energies, gap energy (Eg), global hardness (η), chemical potential (µ), electrophilicity index (ω), maximum charge transfer (ΔNmax), electronegativity (χ), Fermi level (EFL), wavelength (λ), oscillator power (f0), and participation percentage (% Con) for [18] DBA derivatives. A significant increase in the first hyperpolarizability was observed by substitution on [18] DBA. The results of this study may be used to design and construct materials with adjustable electrical properties. The results indicate that the NLO response of [18] DBA could be enhanced by functionalizing different substitutions. In general, the NLO response and electronic properties of the S1-10 are more excellent than others. [ABSTRACT FROM AUTHOR]

The first-principle calculation method based on the density functional theory (DFT) in combination with the LDA+U algorithm is employed to study the electronic structure and magnetic properties of Co/Mn co-doped ZnO nanowires. Special attention is paid to the optimal geometric replacement position, the coupling mechanism, and the magnetic origin of Co/Mn atoms. According to the simulation data, Co/Mn co-doped ZnO nanowires of all configurations exhibit ferromagnetism, and substitution of Co/Mn atoms for Zn in the (0001) inner layer brings nanowires to the ground state. In the magnetic coupling state, the obvious spin splitting is detected near the Fermi level, and strong hybridization effects are observed between the Co/Mn 3d and O 2p states. Moreover, the ferromagnetic ordering forming Co2+-O2−-Mn2+ magnetic path is established. In addition, the calculation results suggest that the magnetic moment mainly takes its origin from the Co/Mn 3d orbital electrons, and the size of the magnetic moment is related to the electronic configurations of Co/Mn atoms. Therefore, a realistic description of the electronic structure of Co/Mn co-doped ZnO nanowires, obtained via LDA+U method, shows their potential for diluted magnetic semiconductor materials. [ABSTRACT FROM AUTHOR]

Bulk III-nitride materials MN (M = Al, Ga and In) and their alloys have been widely used in high-power electronic and optoelectronic devices, but stable two-dimensional (2D) III-nitride materials, except h-BN, have not been realized yet. A new kind of 2D III-nitride material M 2 Si 2 N 4 (M = Al, Ga and In) is predicted by choosing Si as the appropriate passivation element. The stability, electronic and optical properties of 2D M 2 Si 2 N 4 materials are studied systematically based on first-principles calculations. The results show that Al 2 Si 2 N 4 and Ga 2 Si 2 N 4 are found to be indirect bandgap semiconductors, while In 2 Si 2 N 4 is a direct bandgap semiconductor. Moreover, Al 2 Si 2 N 4 and In 2 Si 2 N 4 have good absorption ability in the visible light region, while Ga 2 Si 2 N 4 is an ultraviolet-light-absorbing material. Furthermore, the carrier lifetimes of Ga 2 Si 2 N 4 and In 2 Si 2 N 4 are as large as 157.89 and 103.99 ns, respectively. All these desirable properties of M 2 Si 2 N 4 materials make them attractive for applications in electronics and photoelectronics. [ABSTRACT FROM AUTHOR]

The structural, electronic, and optical properties of pure and Ce-doped BaTiO3 were investigated based on first-principle calculation. Here, we concentrate on understanding the effect of the substitution of Ce for Ba and Ti sites in the equilibrium lattice parameters, DOS, electronic band structure, and optical performance of the materials. The crystal structures with a 12.5% doping ratio at different sites were constructed by superseding an atom of Ba (or Ti) site with a Ce atom and investigating the optimized crystal structure parameters. The substitution of Ce leads to a reduction in the band gap by inducing the movement of the conduction band minimum (CBM) and valence band maximum (VBM). The reduction in the band gap has been shown to be beneficial in increasing electrical conductivity. The density of states of the materials was calculated to gain insight into the valence band, conduction band, and contribution of each orbital to the total density of states in the electronic structure. The charge density, Mulliken charges, and bond overlap populations of pristine and Ce-doped BaTiO3 were calculated to understand the nature of chemical bonds before and after doping. In addition, the optical properties of the materials were calculated, and the substitution of Ce for Ba site increased the static dielectric constant. In contrast, it decreased when Ce was doped into the Ti site. The substitution of Ce for different sites reduced the reflectivity of the material, while the transparency of the materials before and after doping was almost the same. The materials were transparent to incident light when the photon energy was below 10 eV, whereas opacity was in the ultraviolet range of 10–13 eV and beyond 20 eV. The theoretical calculation of different properties provides a new idea for the theoretical study of the BaTiO3-based system. [ABSTRACT FROM AUTHOR]

In this study, we investigate the phase transition of ZnSnN 2 from Pna2 1 to Pmnb using Density Functional Theory (DFT) across a pressure range of 0–70 GPa. Our results show the enthalpy intersection of the Pna2 1 and Pmnb phases at 19.28 GPa, indicating a phase transition from Pna2 1 to Pmnb ZnSnN 2. The decrease in H v of the Pna2 1 phase under pressure before the phase transition is attributed to the reduction of the G and weakening covalent bond of Sn–N pair. The new Pmnb phase exhibits an increased Vickers hardness, Debye temperatures, and brittleness. Moreover, the band gap is an indirect band gap of 1.41 eV due to a rearrangement of lower energy levels for Sn s and p states in conduction band minimum (CMB) and N s and p states in valence band maximum (VBM) at Γ-point. These characteristics make The Pmnb phase promising candidates for applications were longer carrier lifetimes are needed. The mechanical properties, dynamical behavior, and electron localization functions (ELFs) have been investigated and discussed. ZnSnN 2 transitions from the Pna21 to Pmnb phase at 19.28 GPa. The new Pmnb phase shows increased Vickers hardness, Debye temperatures, and brittleness. It also exhibits an indirect band gap of 1.41 eV due to the rearrangement of Sn s and p states in the CBM and N s and p states in the VBM at the Γ-point. [Display omitted] • A phase change is indicated at 19.28 GPa by the enthalpy junction of the Pna21 and Pmnb phases. • For the Pna21 phase under pressure, Vickers hardness (Hv) decreases due to Sn-N bond weakening and a reduction in shear modulus (G). • The Pmnb phase shows a 1.41 eV indirect band gap due to the rearrangement of Sn s and p states at the CBM and N s and p states at the VBM at the Γ-point. • The Pmnb phase is more brittle than the original Pna21 phase post-phase change. [ABSTRACT FROM AUTHOR]

The effects of hydrogen absorption and manganese substitution on structural, electronic, optical, and thermoelectric properties of silicon-carbon nanotubes (SiCNT) are studied using the density functional theory and the GGA approximation. An examination of the PDOS curves and the electronic band structure showed that the Mn substitution leads to an increase in magnetic anisotropy and the occurrence of semi-metallic behavior and that the hydrogen absorption shifts the band gap toward the lower energies. A study of these nanostructures’ thermoelectric behavior reveals that the H absorption leads to a significant escalation in the figure of merit of the SiCNT to about 1.6 in the room temperature range. The effects of the H absorption on this nanotube’s optical properties, including the dielectric functions and its absorption spectra, are also investigated.

Hydrogenated amorphous SiC (a-SiC:H) films with various Si/C ratios were prepared using the plasma-enhanced chemical vapor deposition (PECVD) technique. These films were then subjected to thermal annealing at different temperatures to induce crystallization. The electronic properties of the annealed SiC films were investigated through temperature-dependent Hall mobility measurements. It was found that the room-temperature Hall mobilities in the SiC films increased with both the annealing temperature and the Si/C ratio. This increase was attributed to the improved crystallization in the SiC films. Importantly, SiC films with different Si/C ratios annealed at different temperatures exhibited varying temperature dependence behaviors in their Hall mobilities. To understand this behavior, a detailed investigation of the transport processes in SiC films was carried out, with a particular emphasis on the grain boundary scattering mechanisms.

The electronic, magnetic, and optical properties of PtCoBi half-Heusler compound [001] surfaces and its bulk state have been investigated in the framework of density functional theory using GGA approximation. The half-metallic behaviors of CoBi-term, CoPt-term and PtBi-term decrease with respect to its bulk state. The spin polarization at the Fermi level is 73.2% for the bulk state, and it is –64.4% and –64.1% for the CoBi-term and PtBi-term, respectively while less polarization has been observed for the ­CoPt-term. All terminations have given almost similar optical responses to light. Plasmon oscillations for the terminations occur in the range of 12.5 to 14.5 eV (21 to 22 eV) along xx (zz), and it occurs at 23 eV for the bulk state. The refractive index for the bulk and all three terminations is very high in the infrared and visible areas, meaning a very strong metallic trend in these compounds. The phenomenon of super-luminance occurs for the incident light with energy exceeding 5.5 eV for all three terminations, and it occurs in the range of 10 eV for the bulk mode. These terminations show transparent behavior after the energy of 10 eV.

In this work, Co3O4 nanoparticle-decorated MoS2 (MoS2@Co3O4) hetero-nanoflowers were synthesized by a facile hydrothermal method, and the effect of Co3O4 on the morphological, structural, optical, electronic, and photocatalytic properties of MoS2 was analyzed. The surface morphology of MoS2 and MoS2@Co3O4 was studied via field emission electron microscopy (FE-SEM) and transmission electron microscopy (TEM), which revealed a strong interaction between the MoS2 nanoflower and the nanoparticles. The X-ray diffraction pattern showed a decrease in the crystallite sizes from 7.35 nm to 6.26 nm due to the incorporation of Co3O4. The UV–Vis spectroscopy of the analysis revealed that the indirect band gap of MoS2 was reduced from 1.89 eV to 1.65 eV with the incorporation of Co3O4 nanoparticles. Density functional theory (DFT) calculations were used to investigate the electronic properties of MoS2 and MoS2@Co3O4 hetero-nanoflowers, which also showed a reduction in the electronic band gap for the Co3O4 nanoparticles that were injected. The presence of defect states was also observed in the electronic property of MoS2@Co3O4. The photocatalytic activity of the prepared composite and nanoflower is studied using an aqueous solution of methylene blue (MB), and the efficiencies are found to be 27.96% for MoS2 and 78.89% for MoS2@Co3O4. The improved photocatalytic efficiency of MoS2@Co3O4 hetero-nanoflower can be attributed to narrowing the band gap together with the creation of defect states by the injection of nanoparticles that slows down electron-hole recombination rate by trapping charge carrier. The degradation analysis of the composite provides a new route for the purification of polluted water.

Corrosion inhibition property of a newly synthesized 3-(4-chlorobenzoylmethyl) benzimidazolium bromide inhibitor against carbon steel corrosion in 1 N hydrochloric acid solution was studied and analyzed utilizing various electrochemical methods. Electrochemical impedance study inferred that the inhibition efficiency increased with increasing inhibitor concentration and give 93.5% at 250 ppm. Potentiodynamic polarization study emphasized that inhibitor acted as a mixed type inhibitor and the adsorption of inhibitor on the metal surface followed Langmuir adsorption isotherm. The noise results were in good correlation with other electrochemical results obtained. The increase of inhibition efficiency with concentrations of inhibitor is attributed to the blocking of the active area by the inhibitor adsorption on the metal surface. The thermodynamic parameter values were calculated and discussed to explain the adsorption mechanism of inhibitor in an acidic medium. The protective surface morphology governed by the inhibited medium was investigated using the scanning electron microscopic technique. The surface roughness of the sample in the absence and presence of inhibitor was obtained using atomic force microscopic study. The effect and reactivity of the inhibitor are further clarified with quantum chemical analysis. Finally, the corrosion protection mechanism is proposed on the ground of experimental and theoretical studies. [ABSTRACT FROM AUTHOR]

Element doping is a universal way to improve the electronic and optical properties of two-dimensional (2D) materials. Here, we investigate the influence of group−ⅣA element (C, Si, Ge, Sn, and Pb) doping on the electronic and optical properties of the ZnS monolayer with a tetragonal phase by using first-principles calculations. The results indicate that the doping atoms tend to form tetrahedral structures with neighboring S atoms. In these doped models, the formation energies are all negative, indicating that the formation processes of the doped models will release energy. The formation energy is smallest for C−doped ZnS and gradually increases with the metallicity of the doping element. The doped ZnS monolayer retains a direct band gap, with this band gap changing little in other element doping cases. Moreover, intermediate states are observed that are induced by the sp3 hybridization from the doping atoms and S atoms. Such intermediate states expand the optical absorption range into the visible spectrum. Our findings provide an in-depth understanding of the electronic and optical properties of the ZnS monolayer and the associated doping structures, which is helpful for application in optoelectronic devices. [ABSTRACT FROM AUTHOR]

The primary objective of contemporary manufacturing is to produce items that are low-cost, environmentally friendly, and energy efficient. This study aimed to investigate compounds that fulfil these criteria, with a focus on CdCrO3. The full potential linearized augmented plane wave program (FP LAPW), as in Wien2K, was employed to examine the structural, electronic, thermodynamic, and transport characteristics of the material. Structural optimization was carried out using generalized gradient approximation (GGA), with lattice constants that were deemed satisfactory based on previous theoretical and experimental results. Calculations of the magnetic characteristics of CdCrO3 show that the Cr atoms are principally responsible for magnetism. The quasi-harmonic Debye model allows for the identification of thermodynamic properties including trends, the relative Debye temperature, thermal expansion parameter, relative volume, and heat capacity at various pressures and temperatures. At constant volume, a heat capacity of 52 J/mol K was determined. The thermoelectric properties were examined using the Boltzmann transport offered by the BoltzTrap program. At room temperature, CdCrO3 had a figure of merit (ZT) value that was almost equal to one, indicating that it may be used to make thermoelectric devices with the highest possible efficiency.

The growth behavior, stability, electronic and magnetic properties of the Gd2Sin− (n = 3–12) clusters are reported, which are investigated using density functional theory calculations combined with the Saunders ‘Kick’ and the Artificial Bee Colony algorithm. The lowest-lying structures of Gd2Sin− (n = 3–12) are all exohedral structures with two Gd atoms face-capping the Sin frameworks. Results show that the pentagonal bipyramid (PB) shape is the basic framework for the nascent growth process of the present clusters, and forming the PB structure begins with n = 5. The Gd2Si5− is the potential magic cluster due to significantly higher average binding energies and second order difference energies, which can also be further verified by localized orbital locator and adaptive natural density partitioning methods. Moreover, the localized f-electron can be observed by natural atomic orbital analysis, implying that these electrons are not affected by the pure silicon atoms and scarcely participate in bonding. Hence, the implantation of these elements into a silicon substrate could present a potential alternative strategy for designing and synthesizing rare earth magnetic silicon-based materials.

Introducing Sn atoms induces structural transformation of ZnIn 2 S 4 (ZIS) from 3D microspheres to 2D ultrathin nanosheets. This process leads to reduction in band gap, elevation in carrier concentration, and activation of inert basal plane. Such an ingenious triple-benefit approach involving microstructure optimization, electronic property modulation and active site modification, brings about significant enhancement in photocatalytic H 2 evolution activity of ZIS. [Display omitted] • Ultrathin Sn-ZIS nanosheets are prepared via a facile one-step hydrothermal process without surfactant. • DFT calculations and XAFS studies demonstrate the substitution of Zn atoms on ZIS surface layer by Sn atoms. • The morphology, electronic structure, and active site of ZIS can be simultaneously modulated through Sn atom doping. • The photocatalytic HER activity of Sn-ZIS is 6.7 and 3.5 times that of pure ZIS and Pt@ZIS, respectively. To overcome the high cost and complex preparation of cocatalysts in photocatalytic H₂ production, this study pioneers a triple-benefit strategy in visible-light-absorbing semiconductors through microstructure optimization, electronic property modulation, and active site modification in two-dimensional (2D) hexagonal ZnIn₂S₄ (ZIS) via Sn atom doping. Facilely synthesized through a one-step hydrothermal method without surfactants, 4–6 nm thick Sn-doped ZIS nanosheets exhibit reduced charge recombination by preventing excessive self-assembly and aggregation. Density Functional Theory (DFT) and X-ray Absorption Fine Structure (XAFS) confirm Sn's substitution for Zn on (0 0 1) surface, shifting the Fermi level into the conduction band to facilitate electron migration and charge separation. This adjustment also modulates the electronic properties of adjacent S atoms, triggering the inert basal plane for an enhanced H₂ evolution reaction kinetics. Consequently, Sn-ZIS achieves a H₂ evolution rate of 62.18 μmol h−1 under visible light, significantly outperforming pure ZIS and Pt@ZIS by 6.7 and 3.5 times, respectively. [ABSTRACT FROM AUTHOR]

Chalcogenide perovskites offer superior thermal and aqueous stability as well as a benign elemental composition compared to organic halide perovskites for optoelectronic applications. In this study, the structural, electrical, elastic, phonon dispersion, and thermodynamic features of the orthorhombic phase of chalcogenide perovskite CaZrS_3 (space group Pnma) were examined by first principles calculations utilizing the plane wave pseudopotentials (PW-PPs) in generalized gradient approximations (GGA). The ground state properties such as lattice parameters, unit cell volume, bulk modulus, and its derivative were calculated and are in a good agreement with existing findings. The mechanical properties such as bulk modulus, shear modulus, Young's modulus and elastic anisotropy were calculated from the obtained elastic constants. The ratio of bulk modulus to shear modulus confirms that the orthorhombic phase of CaZrS_3 is a ductile material. The absence of negative frequencies in phonon dispersion curve and the phonon density of states give an indication that the structure is dynamically stable. Finally, thermodynamic parameters such as free energy, entropy, and heat capacity were calculated with variation in temperature. The estimated findings follow the same pattern as previous efforts.

In this paper, N ions are implanted into ZnO and ZnAlO films with different carrier concentrations prepared by radio frequency reactive magnetron sputtering on sapphire substrates. The structural, electrical, optical and magnetic properties of N-doped and (Al, N) co-doped ZnO films is investigated, and the particular emphasis is placed on the effects of carrier concentration on the defects induced magnetism in the films. Our results show that all the doped ZnO films are ferromagnetic at room temperature. A trace amount of additional Al doping has a significant effect on the improvement of ferromagnetic properties, and a maximum saturation magnetization of 73 emu/cm3 is obtained for (Al, N) co-doped ZnO films. The optical band gaps of ZnO films increase with the increasing Al doping content, which is owing to the combined effect of high carrier concentration and the Burstein Moss effect. The average transmittance of all ZnO films exceeds 80%. Our results confirm that appropriate electron doping can effectively enhance the magnetic moment in N implanted ZnO which may also apply to other ZnO systems with d0 magnetism. • N-doped ZnO and AZO films were made by ion implantation and thus contain both N ions and defects due to implantation. • The band gap and carrier concentration of ZnO films increase after Al doping. • Electron doping can effectively enhance the d0 magnetism in the N doped films. • Magnetization was correlated with lattice defects and carrier concentration. [ABSTRACT FROM AUTHOR]

We use first‐principles‐based density functional theory (DFT) calculations to investigate the structural, elastic, and electronic properties of various pristine and oxygen (O)‐functionalized double transition metal (DTM) MXenes with general formulas of M2′M′′C2 and M2′M′′C2O2, where M′ = Mo, Cr and M′′ = Ti, V, Nb, Ta. The dynamic stability of the DTM MXenes are assessed and elastic stiffness constants (Cij) are used to investigate the mechanical stability and properties of the compositions. The calculated elastic properties of the pristine Mo‐based MXenes are found to be superior compared to Cr‐based compounds. Furthermore, the O‐functionalized MXenes exhibit improved in‐plane elastic constants, Young's moduli, and shear moduli compared to their pristine counterpart. We observe that the hybridization of the energy states results in stronger covalent interactions as such increased elastic properties for the M2′M′′C2O2 MXenes. Ashby plot clearly demonstrates superior materials properties of O‐functionalized Mo‐based DTM MXenes compared to other commonly known two‐dimensional materials. All the MXenes exhibit metallic character evident from the density of states (DOS) calculations. Additionally, the work functions are studied and the calculated values are higher in the case of O‐functionalized MXenes. Overall, this work will be a guide for future investigations on the mechanical properties of DTM MXenes for their targeted applications in structural nanocomposites. [ABSTRACT FROM AUTHOR]

The electronic properties of single-walled carbon nanotubes (SWCNTs) are potentially useful for electronics, optics, and sensing applications. Depending on the chirality and diameter, individual SWCNTs can be classified as semiconducting (S-SWCNT) or metallic (M-SWCNT). From a biological perspective, the hazard profiling of purified metallic versus semiconducting SWCNTs has been pursued only in bacteria, with the conclusion that aggregated M-SWCNTs are more damaging to bacterial membranes than S-SWCNTs. However, no comparative studies have been performed in a mammalian system, where most toxicity studies have been undertaken using relatively crude SWCNTs that include a M:S mix at 1:2 ratio. In order to compare the toxicological impact of SWCNTs sorted to enrich them for each of the chirality on pulmonary cells and the intact lung, we used density gradient ultracentrifugation and extensive rinsing to prepare S- and M-SWCNTs that are >98% purified. In vitro screening showed that both tube variants trigger similar amounts of interleukin 1β (IL-1β) and transforming growth factor (TGF-β1) production in THP-1 and BEAS-2B cells, without cytotoxicity. Oropharyngeal aspiration confirmed that both SWCNT variants induce comparable fibrotic effects in the lung and abundance of IL-1β and TGF-β1 release in the bronchoalveolar lavage fluid. There was also no change in the morphology, membrane integrity, and viability of E. coli, in contradistinction to the previously published effects of aggregated tubes on the bacterial membrane. Collectively, these data indicate that the electronic properties and chirality do not independently impact SWCNT toxicological impact in the lung, which is of significance to the safety assessment and incremental use of purified tubes by industry.

The strain-controlled structural, electronic, and optical characteristics of monolayer β-AuSe are systematically studied using first-principles calculations in this paper. For the strain-free monolayer β-AuSe, the structure is dynamically stable and maintains good stability at room temperature. It belongs to the indirect band gap semiconductor, and its valence band maximum (VBM) and conduction band minimum (CBM) consist of hybrid Au-d and Se-p electrons. Au–Se is a partial ionic bond and a partial polarized covalent bond. Meanwhile, lone-pair electrons exist around Se and are located between different layers. Moreover, its optical properties are anisotropic. As for the strained monolayer β-AuSe, it is susceptible to deformation by uniaxial tensile strain. It remains the semiconductor when applying different strains within an extensive range; however, only the biaxial compressive strain is beyond −12%, leading to a semiconductor–semimetal transition. Furthermore, it can maintain relatively stable optical properties under a high strain rate, whereas the change in optical properties is unpredictable when applying different strains. Finally, we suggest that the excellent carrier transport properties of the strain-free monolayer β-AuSe and the stable electronic properties of the strained monolayer β-AuSe originate from the p–d hybridization effect. Therefore, we predict that monolayer β-AuSe is a promising flexible semiconductive photoelectric material in the high-efficiency nano-electronic and nano-optoelectronic fields. [ABSTRACT FROM AUTHOR]

The effects of hydrogen absorption and manganese substitution on structural, electronic, optical, and thermoelectric properties of silicon-carbon nanotubes (SiCNT) are studied using the density functional theory and the GGA approximation. An examination of the PDOS curves and the electronic band structure showed that the Mn substitution leads to an increase in magnetic anisotropy and the occurrence of semi-metallic behavior and that the hydrogen absorption shifts the band gap toward the lower energies. A study of these nanostructures' thermoelectric behavior reveals that the H absorption leads to a significant escalation in the figure of merit of the SiCNT to about 1.6 in the room temperature range. The effects of the H absorption on this nanotube's optical properties, including the dielectric functions and its absorption spectra, are also investigated. [ABSTRACT FROM AUTHOR]

The electronic and optical properties of three types of aluminum phosphide bilayers are examined using density functional theory. The results indicate that they all possess proper direct gaps, which exhibit a rich variety of behaviors depending on the strain. The band gaps of these aluminum phosphide bilayers could be easily tuned in the energy range from 0 eV to 1.9 eV under a wide range of biaxial strain. Additionally, band gap transitions between direct and indirect types are found when the external strain applied on them is changed from −12% to 12%. In addition, it was found that these AlP bilayers show strong light-harvesting ability for the ultraviolet light range of the solar spectrum (400–100 nm). The results obtained here indicate that these aluminum phosphide bilayers may have significant potential applications in future nanoelectric fields.