Electronic Behavior Research Articles

Structural and electronic properties of amorphous silicon and germanium monolayers and nanotubes: A DFT investigation

A recent breakthrough has been achieved by synthesizing monolayer amorphous carbon (MAC). Here, we used ab initio (DFT) molecular dynamics simulations to study silicon and germanium MAC analogs. Typical unit cells contain more than 600 atoms. We also considered their corresponding nanotube structures. The cohesion energy values for MASi and MAGe are approximately 3.0 eV/atom lower than the energy ordering of silicene and germanene, respectively. Their electronic behavior varies from metallic to small band gap semiconductors. Since silicene, germanene, and MAC have already been experimentally realized, the corresponding MAC-like versions we propose are within our present synthetic capabilities.

From Metals to Semiconductors: Advancing MXY (M = Ti, Sn, Ir, X = Se, Te, Y = Se, Te) Compounds with Strain Engineering—A Computational Perspective

In this computational study, density functional theory (DFT) is employed to analyze the structural, electronic, elastic, and topological properties of ternary compounds MXY (M = Ti, Sn, Ir, X = Se, Te, Y = Se, Te). The effects of spin–orbit interaction and pressure‐induced strain are investigated to understand their influence on the stability, mechanical properties, and electronic behavior, paving the way for potential technological applications. The findings confirm that these compounds are inherently stable in nonmagnetic phases, with spin–orbit interaction critically influencing their energy–volume landscapes. The calculated lattice parameters, ratios of lattice constants, and bulk moduli closely align with existing data, confirming the reliability of our approach. Mechanical assessments reveal distinct behaviors: IrSe2 exhibits the highest stiffness due to pronounced covalent bonding, contrasting with SnTe2's elastic anisotropy and SnSeTe's nearly isotropic properties. Electronically, most compounds show metallic characteristics, except SnSe2, which behaves as a semiconductor with an indirect, pressure‐sensitive energy bandgap. Topological analysis under varying hydrostatic pressures indicates band inversions in TiSe2, IrSe2, and SnSeTe, suggesting topological phase transitions absent in other compounds. This study enriches our understanding of these materials and refines the application of DFT in material design.

Electronic structures, elastic behaviors and magnetic properties of monolayer [formula omitted] and [formula omitted] Ni[formula omitted]I[formula omitted]

This study investigates the electronic structures, elastic behaviors, and magnetic properties of monolayer Ni2I2 in two novel phases, P3̄m1 and P4/nmm, using first-principles calculations and Monte Carlo simulations. The electronic structures of P3̄m1 and P4/nmm phases show half-metallic properties with spin magnetic moments of 0.85 and 0.82 μB respectively. Both phases exhibit mechanical and dynamic stability. The P3̄m1 phase has isotropic elastic properties and good ductility, while the P4/nmm phase shows significant crystallographic anisotropy. The spin exchange coupling constants between the nearest and the next-nearest neighbor Ni ions in the P4/nmm phase are nearly an order of magnitude higher than those in the P3̄m1 phase, with the former having a Curie temperature close to room temperature at 296 K, significantly higher than the 27 K of the latter. The strain modulation range for structural and magnetic phase transitions between the P3̄m1 and P4/nmm phases is provided theoretically.

The Relationship between Electronic Marketing and Consumer Behavior "An Applied Study on a Sample of Customers of Al-Rafidain Bank – Iraq"

The current research aims to understanding the relationship between e-marketing and consumer behavior through study applied to a sample of Rafidain Bank customers, and the current research focuses on surveying the opinions of a sample of customers dealing with Rafidain Bank in three Iraqi governorates (Babil, Karbala, and Najaf), numbering (325) Customers. the researcher examined, through a set of hypotheses, the effects of the independent variable, which is electronic marketing, on consumer behavior, and consequently the effects of the latter on the bank’s profitability. A questionnaire was designed to survey the opinions of the individuals in the aforementioned research sample, according to a scale to be respected the quintet, and these phrases included five axes distributed between the study variables, demographic information of the study sample, elements of electronic marketing, elements supporting electronic marketing, indicators of the efficiency of banking services, and finally consumer behavior. The descriptive analysis resulted in tables that displayed the initial statistical results and analytical results that address the research hypotheses, whether negative or positive. the study reached the following conclusions the most important of which is that The dimensions of consumer behavior are arranged as follows: education, attitudes, perception, motives, and finally, the study proved the existence of a strong relationship between the independent variable and the mediator on the bank's profitability clearly, so the recommendations were confirmed that this relationship should be under the attention of the relevant parties in the upper and middle management and that they should take it into account when working on developing the marketing mix strategies for banking services at Rafidain bank to enhance its pioneering role in banking work at the level of Iraq and the world.

Unraveling the Stability and Magnetic Properties of Bis-Hydrated Mn(II) Complexes via Tailored Ligand Design.

Exploring the electronic structure and dynamic behavior of Mn(II) complexes reveals fascinating magnetic properties and prospective biomedical applications. In this study, we investigate the solvent phase dynamics of heptacoordinated Mn(II) complexes through ab initio molecular dynamics simulations and density functional theory (DFT) calculations with effectively varying temperatures. We observed that the complex with high stability ([Mn(pmpa)(H2O)2]) remains relatively rigid as the temperature increases to 90 °C, with only a minor change in its radial distribution functions (RDFs), compared to the RDF peaks at 25 °C. To elucidate the impact of halogens on the magnetic anisotropy of seven-coordinated Mn(II) complexes, we performed both DFT and multireference calculations. This shows that the zero-field splitting (ZFS) parameter D follows the order D(I)> D(Br)> D(Cl). We observed a significant increase in the D-value following the substitution of soft Se-donors in the equatorial position and heavier halogens in the axial position. The D-value of halogen derivatives of Se-analogues varies in the order of D(Cl) < D(I) < D(Br), deviating from the regular spectrochemical series with the discrepancy between the covalency of the Mn(II)-Se bond and the ligand field strength. We anticipate that this study will enhance our understanding of the solvent phase dynamics and structural aspects of ZFS in various Mn(II) complexes with different electronic environments.

Механизмы электронного транспорта в низкоразмерных полупроводниковых структурах: обзор

Background: Low-dimensional semiconductor structures such as quantum wells, wires, and dots have sparked widespread attention due to their distinct electron transport properties that differ dramatically from bulk materials. These characteristics are critical for advances in nanoscale electrical and optoelectronic devices. Objective: The article aims to summarize current knowledge of electron transport processes in low-dimensional semiconductor devices, focusing on the impact of reduced dimensionality on electron behaviour. Methods: A thorough literature analysis was carried out, emphasizing experimental and theoretical investigations that shed light on electron transport dynamics in quantum wells, wires, and dots. The analysis looked into scattering mechanisms, quantum confinement effects, and the significance of material composition and structure. Results: The findings show that quantum confinement produces discrete energy states that drastically change electron mobility and conductivity. Furthermore, electron scattering by phonons, contaminants, and surfaces is shown to be heavily impacted by decreased dimensionality, which either enhances or suppresses electron transport depending on the precise configuration and size of the structures. Conclusion: Low-dimensional semiconductor structures have complex electron transport behaviours that differ significantly from their bulk counterparts. Understanding these mechanisms is critical for designing and developing future electronic devices, and this overview serves as a starting point for ongoing articles on this technologically significant topic.

Enhancing the Performance of Nanocrystalline SnO2 for Solar Cells through Photonic Curing Using Impedance Spectroscopy Analysis.

Wide-bandgap tin oxide (SnO2) thin-films are frequently used as an electron-transporting layers in perovskite solar cells due to their superior thermal and environmental stabilities. However, its crystallization by conventional thermal methods typically requires high temperatures and long periods of time. These post-processing conditions severely limit the choice of substrates and reduce the large-scale manufacturing capabilities. This work describes the intense-pulsed-light-induced crystallization of SnO2 thin-films using only 500 μs of exposure time. The thin-films' properties are investigated using both impedance spectroscopy and photoconductivity characteristic measurements. A Nyquist plot analysis establishes that the process parameters have a significant impact on the electronic and ionic behaviors of the SnO2 films. Most importantly, we demonstrate that light-induced crystallization yields improved topography and excellent electrical properties through enhanced charge transfer, improved interfacial morphology, and better ohmic contact compared to thermally annealed (TA) SnO2 films.

Synthesis and anticancer activity of Pd(II) and Pt(II) complexes of dodecyl based dithiocarbamate ligands: Insight into the C-H∙∙∙Pt interaction using X-ray structure, DFT, Hirshfeld surface and AIM analysis

Four new homoleptic complexes bis(N-dodecyl-N-benzyl)dithiocarbamato-S,S’)M(II) (where M=palladium (1), platinum (3)) and bis(N-dodecyl-N-(2-hydroxybenzyl)dithiocarbamato-S,S’)M(II) (where M=palladium (2), platinum (4)) were synthesized and characterized using elemental analysis, FTIR and NMR spectra. The crystal structures of 1 and 4 were solved by single crystal X-ray diffraction technique. Single crystal X-ray analysis of the two of the complexes (1 and 4) revealed the presence of a distorted square planar coordination geometry (S4) about the metal centre. Complex 4 revealed two intermolecular anagostic C-H∙∙∙Pt interactions which were characterized through a comprehensive set analysis using single crystal X-ray diffraction (experimental) and DFT, Hirshfeld surface analysis and AIM (theoretical) analysis. The electronic behavior, MEP surfaces, FMO and DOS studies of the complexes 1 and 4 were investigated employing DFT. A strong correlation has been found between both experimental and theoretical bond parameters. MTT assay was used to study the antitumor activities of 1–4 against MCF7 cancer cells. The results reveal that all complexes have fine anticancer activities.

Three-dimensional valley-contrasting sound.

Spin and valley are two fundamental properties of electrons in crystals. The similarity between them is well understood in valley-contrasting physics established decades ago in two-dimensional (2D) materials like graphene-with broken inversion symmetry, the two valleys in graphene exhibit opposite orbital magnetic moments, similar to the spin-1/2 behaviors of electrons, and opposite Berry curvature that leads to a half topological charge. However, valley-contrasting physics has never been explored in 3D crystals. Here, we develop a 3D acoustic crystal exhibiting 3D valley-contrasting physics. Unlike spin that is fundamentally binary, valley in 3D can take six different values, each carrying a vortex in a distinct direction. The topological valley transport is generalized from the edge states of 2D materials to the surface states of 3D materials, with interesting features including robust propagation, topological refraction, and valley-cavity localization. Our results open a new route for wave manipulation in 3D space.

Enhancing the photovoltaic properties of phenothiazine-based chromophores via structural integration of selenophene analogues

A series of oligomer-type donor photovoltaic materials (MP2–MP9) were designed via the incorporation of selenophene unit (n = 1–8) in MP1 as π-spacer. In order to accomplish the electronic, photophysical, and photovoltaic (PV) behavior of MPR and MP1–MP9, quantum chemical calculations were performed through the density functional theory (DFT) approach. The M06/6-311G (d,p) level was selected for current investigation through a benchmark study between experimental and DFT values of λmax at various functionals of MPR compound. Descending in energy gap (3.058–2.476 eV) with wider absorption wavelength (652.998–513.392 nm) in dichloromethane along with greater charge transmission were probed with the addition of selenophene unit as compared to MPR. The studied chromophores were perceived to have Voc and FF ranging from 1.320–1.728 V and 0.903–0.923 %, respectively. These findings provide valuable insights into the design of oligomer-type donor materials with optimized electronic and photophysical properties, which could enhance the performance and efficiency of organic photovoltaic devices.

Influence of nitrogen exchange in the core-shell structure of naphthalenediimide molecules on the advancement of quantum electronic properties

This study explores how nitrogen substitution and gold electrodes collectively influence the electronic characteristics of naphthalenediimide (NDI) molecules (M = 1, 2, and 3) through theoretical analysis. Utilizing ELF, LOL, QTAIM, and NCI analyses, we reveal significant alterations in NDI's electronic structure and interactions upon bonding with gold electrodes (Au-M-Au). Both ELF and LOL analyses demonstrate increased electron localization and delocalization on the NDI surface due to gold electrodes, with a stronger effect on nitrogen-doped molecules (M = 2, 3). QTAIM analysis confirms favorable non-covalent interactions, including evident hydrogen bonding, between NDI molecules and gold electrodes, notably intensified in doped molecules, especially the Au…O interaction. NCI analysis provides insight into the diverse interactions within the molecular system. Overall, this research highlights the crucial role of gold electrodes and nitrogen substitution in fine-tuning NDI molecules' electronic properties. The observed modulation of electron behavior and formation of beneficial interactions with gold electrodes hint at promising applications for doped NDI-gold systems requiring efficient charge transport mechanisms.

Highly efficient SnO2-Carbon nanosphere heterojunctions decorated with Ag for detecting isopropanol at low operating temperatures

The design of a sensing material for detecting isopropanol gas with low operating temperature is extremely important for miniaturization and wearability of gas sensors. Herein, a novel gas sensor based on SnO2-Carbon nanosphere heterojunctions decorated with Ag nanoparticles (SCA) was fabricated and its gas sensing performance was evaluated and compared systematically. The measurement results indicated that the sensing performance was influenced by the ratio of Sn/C and the length of Ag plating, and the SCA sensor provided the best response. For 100 ppm isopropanol at 100 °C, the SCA sensor exhibited a response value of 50.51, a response time of 7 s and a recovery time of 60 s. The enhanced sensing performance and reduced operating temperature of the SCA could be attributed to the synergistic effect of the SnO2-Carbon nanosphere heterojunctions and the significant catalytic performance of the decorated Ag nanoparticles. In addition, the density functional theory calculation method based on the first-principles theory was used to study the adsorption performance and electronic behavior, as well asthe influence of Ag decoration on SnO2 for isopropanol detection. The calculated results were consistent with the experimental results.

EXPLORING THE STRUCTURAL AND ELECTRONIC CHARACTERISTICS OF AMORPHOUS Ge – Te - In MATERIAL THROUGH AB INITIO METHODS

This study employs density functional theory (DFT) and molecular dynamics to meticulously investigate the structural and electronic properties of ternary chalcogenide compounds, specifically (GeTe4 ) 1-x Inx, and (GeTe5 )1-x Inx across a range of compositions ( x = 0, 5, 10, 15, 20 at %). Utilizing the local density approximation within the framework of first-principles calculations, we comprehensively analyze the pair correlation function, static structural factor, electronic density of states, and electronic band gap energy. Our results reveal a notable decrease in the energy band gap of Germanium-Tellurium with the incorporation of Indium atoms. The structural changes observed in the Ge-Te matrix with Indium doping, as evidenced by the changes in the pair correlation function and static structure factor, are consistent with and supportive of the observed decrease in the band gap energy. This phenomenon is primarilyattributed to the significant contribution of Indium atoms to the conduction band edge, offering new insights into the material’s electronic behaviour.

Detailed DFT based exploration on spin-gapless features of IrCoNbX (X=Al, Ga, In) alloys

An investigation has been conducted on the spin-polarized structural, electronic, charge transfer, −COHP and magnetic behaviour of IrCoNbX (X=Al, Ga, In) alloys. To corroborate the studied properties the generalized gradient approximation (GGA), modified Becke Johnson (mBJ) and DFT+U schemes within the framework of density functional theory. The structures found comparatively more stable in spin-polarized phase than non-spin polarized phase. Based on electronic band structure and electronic density of states’ analysis IrCoNbX alloys have demonstrated spin-gapless features in spin ↑ channel and semiconducting characteristics in spin ↓ channel. The −COHP examination revealed that Nb-Ir pair exhibited significantly stronger bonding interaction in comparison to XCo (XAl, Co, In, Nb) bonding pairs in IrCoNbX alloys. Each of the studied alloys manifested an integer value of the total magnetic moment of 2.0 μB/f.u under mBJ scheme. The findings of current study proposed the experimental investigation of these alloys for potential applications in spintronics field.

Potential improvement in thermoelectric properties of SnTe polycrystals via anionic and cationic substitution

Heat is produced by all machinery, including microprocessors and jet engines, as well as by industrial processes that produce goods from steel to food. There is still a strong desire for alternative energy sources in this day of ecologically conscious and sustainable energy needs. The recovery of heat from waste heat into beneficial electrical energy provides a simple energy source with enormous potential. Thermoelectrics is one of the popular technologies, which can convert heat into electricity, making them useful for power generation. Tin telluride (SnTe), a significant type of newly developed thermoelectric material, has drawn a lot of attention due to its low toxicity and environmentally friendly characteristics. Here, we synthesize Bi/Se co-doped SnTe (Sn1-xBixTe0.97Se0.03 (x = 0, 0.02, 0.04, 0.06)) samples by employing the solid-state metathesis route. The results of this work suggest that the combined action of cationic and anionic substitution of Bi and Se to SnTe matrix could potentially modify the microstructure and band structure of SnTe, thereby effectively improving its electronic, mechanical, and thermal transport properties. In line with the experimental findings, the samples show degenerate semiconducting electronic transport behaviour throughout the temperature range. The maximum Seebeck coefficient is found to be ∼84 μV/K and the total thermal conductivity is reduced to 1.6 W/mK at 573 K in a 6 % Bi-doped sample, which is 2.2 times less than the pristine sample. The Sn0.94Bi0.06Te0.97Se0.03 sample has a maximum ZT of approximately 0.23 at 573 K, which is three times higher than the pristine sample because of the combined regulation of cation-anion co-doping and an elevated power factor of 936 μW/K2m in Sn0.96Bi0.04Te0.97Se0.03 sample at 573 K, which is 1.82 times higher than that of pristine SnTe. Considering these findings, it appears that Bi-Se co-doped SnTe is a promising material for thermoelectric applications.

Mechanism of Pressure-Modulated Self-Trapped Exciton Emission in Cs2TeCl6 Double Perovskite.

Pressure-modulated self-trapped exciton (STE) emission mechanism in all-inorganic lead-free metal halide double perovskites characterized by large Stokes-shifted broadband emission, has attracted much attention across various fields such as optics, optoelectronics, and biomedical sciences. Here, by employing the all-inorganic lead-free metal halide double perovskite Cs2TeCl6 as a paradigm, the authors elucidate that the performance of STE emission can be modulated by pressure, attributable to the pressure-induced evolution of the electronic state (ES). Two ES transitions happen at pressures of 1.6 and 5.8GPa, sequentially. The electronic behaviors of Cs2TeCl6 can be jointly modulated by both pressure and ES transitions. When the pressure reaches 1.6GPa, the Huang-Rhys factor S, indicative of the strength of electron-phonon coupling, attains an optimum value of ≈12.0, correlating with the pressure-induced photoluminescence (PL) intensity of Cs2TeCl6 is 4.8-fold that of its PL intensity under ambient pressure. Through analyzing the pressure-dependent STE dynamic behavioral changes, the authors have revealed the microphysical mechanism underlying the pressure-modulated enhancement and quenching of STE emission in Cs2TeCl6.

Surface-sensitive electronic structure of kagome superconductor CsV3Sb5

Abstract We systematically study the electronic structure of a kagome superconductor CsV3Sb5 at different temperatures covering both its charge density wave state and normal state with angle-resolved photoemission spectroscopy. We observe that the V-shaped band around Γ ¯ shows three different behaviors, referred to as α/α′, β and γ, mainly at different temperatures. Detailed investigations confirm that these bands are all from the same bulk Sb-p z origin, but they are quite sensitive to the sample surface conditions mainly modulated by temperature. Thus, the intriguing temperature dependent electronic behavior of the band near Γ ¯ is affected by the sample surface condition, rather than intrinsic electronic behavior originating from the phase transition. Our result systematically reveals the confusing electronic structure behavior of the energy bands around Γ ¯ , facilitating further exploration of the novel properties in this material.

Effect of multi-temperature models on heat transfer and electron behavior in hypersonic flows

In hypersonic computational fluid dynamics, the two-temperature (2-T) model is widely used to simulate thermochemical nonequilibrium. The 2-T model incorporates translational-rotational and electron-electronic-vibrational energies, assuming that the integrated energies have the equivalent temperature. In this study, multi-T models are constructed to accurately predict the effects on heat flux and free electrons due to the separation of energy modes under hypersonic environments. The three-temperature (3-T) model separates the electron-electronic energy from the electron-electronic-vibrational energy of the 2-T model. The 3-T model can accurately predict the distribution and temperature of free electrons by separating the energy of free electrons, which has different characteristics from heavy particles. The four-temperature model treats rotational energy as a nonequilibrium energy mode, distinct from translational-rotational energy. While the rotational temperature reaches equilibrium rapidly at low temperatures, at high-temperature regime rotational temperature shows a relaxation time similar to that of vibrational temperature, which cannot be ignored. To develop multi-T models, electron-vibrational relaxation and translational-rotational relaxation, which are omitted in the 2-T model, are considered. Various flight test and ground facility conditions are analyzed to verify the effects of electron and heat flux under circumstances that include shock, expansion, and shock wave boundary layer interaction. The results of the multi-T models show significant differences in electron temperature and distribution caused by electron-electronic nonequilibrium. Additionally, rotational nonequilibrium increases the shock standoff distance and alters the electron distribution at high altitudes. The heat flux difference across multi-T models is found to be negligible, except in the high degree of ionization condition.

Computer-Aided Drug Design Using the Fragment Molecular Orbital Method: Current Status and Future Applications for SBDD.

Owing to the increasing use of computers, computer-aided drug design (CADD) has become an essential component of drug discovery research. In structure-based drug design (SBDD), including inhibitor design and in silico screening of drug target molecules, concordance with wet experimental data is important to provide insights on unique perspectives derived from calculations. Fragment molecular orbital (FMO) method is a quantum chemical method that facilitates precise energy calculations. Fragmentation method makes it possible to apply the quantum chemical method to biological macromolecules for energy calculation based on the electron behavior. Furthermore, interaction energies calculated on a residue-by-residue basis via fragmentation aid in the analysis of interactions between the target and ligand molecule residues and molecular design. In this review, we outline the recent developments in SBDD and FMO methods and highlight the prospects of developing machine learning approaches for large computational data using the FMO method.

Hirshfeld surface, fukui function, molecular docking, molecular dynamics investigation on human immunodeficiency virus-1 (HIV) organism with 2,6-dibromo-4-chloroaniline

2,6-Dibromo-4-chloroaniline is a planar molecule. Functional analysis based on vibrational modes is made clearer by spectral analysis. Quantum chemical calculation are characterized, its electronegativity in addition to local characteristics such as electrophilicity and Fukui function. ELF study aims to understand the quantitative behavior of electrons within a system. Docking simulation has been used to assess the energy of binding and coupling between the enhanced protein and ligand combination molecules. The research and development of new drugs heavily relies on the chemical properties of toxicity, metabolism, excretion, distribution, and absorption. The Hirshfeld surface was a helpful tool for illustrating characteristics, such as the electrostatic potential of a molecule inside a crystal structure, that could be quickly and easily learned.