WIEN2k Code Research Articles

Ab initio study of the structural, electronic, and optical properties of MgTiO3 perovskite materials doped with N and P

This study investigates the electronic, optical, and structural properties of MgTiO3 perovskite materials, whether pure or doped with elements such as nitrogen (N) and phosphorus (P). The investigation utilizes density functional theory (DFT) with the GGA-mBJ approximation as implemented in the Wien2k code. The results show that the band gap energy of doped MgTiO3 is significantly lower than that of pure MgTiO3, which has a band gap of 2.933 eV, at oxygen sites with Y (N, and P). In particular, with N and P, the band gaps drop to 1.74 and 0.65 eV moreover, the Fermi energy (Ef) level shifts towards the valence band (VB) in a p-type semiconductor (SC). Further, we have analyzed the optical characteristics of these systems, including their dielectric function (ε1 and ε2), optical conductivity (σ), absorption coefficient (α), and refractive index (n). Furthermore, doping with N and P increases absorption in the visible spectrum, which raises the photocatalytic activity in the presence of light because the doped materials’ valence and conduction bands transition more readily, producing hydrogen. The discoveries above suggest that these materials possess a broad spectrum of applications, encompassing the creation of optoelectronic apparatus.

FIRST-PRINCIPLES CALCULATION OF STRUCTURAL, ELECTRONIC, AND OPTICAL PROPERTIES OF InP1-XSbX USING WC-mBJ FOR NANOSCALE IR APPLICATIONS

The structural, electronic, and optical characteristics of cubic InP<sub>1-x</sub>Sb<sub>x</sub>(x = 0, 0.25, 0.50, 0.75, 1) ternary alloys were explored using the full-potential linearized augmented plane wave density functional theory approach. The total energy vs. volume optimization, lattice constants, and density of states were investigated for InP<sub>1-x</sub>Sb<sub>x</sub> alloys using exchange correlation function Wu-Cohen generalized gradient approximation (WC-GGA), available with the WIEN2k code. Band structure of the alloys was calculated using TB-mBJ functional to achieve a higher bandgap accuracy. The results of the mBJ experiment are in close agreement to those of the other experimental studies when compared to WC-GGA. Dielectric function and energy loss function were calculated in order to explore optical properties of the alloys. It was noticed that the estimated lattice parameters exhibit reduction when the Sb content is increased. Furthermore, the compositional dependency of the structural, electronic, and optical properties were also reported. For the InP<sub>1-x</sub>Sb<sub>x</sub> alloys, a band gap of less than 1.6 eVwere observed, making it suitable for usage in infrared optoelectronics devices.

Investigation of half metallic properties of Tl2Mo(Cl/Br)6 double perovskites for spintronic devices.

The manipulation of electronic device characteristics through electron spin represents a burgeoning frontier in technological advancement. Investigation of magnetic and transport attributes of the Tl2Mo(Cl/Br)6 double perovskite was performed using Wien2k and BoltzTraP code. When the energy states between ferromagnetic and antiferromagnetic conditions are compared, it is evident that the ferromagnetic state exhibits lower energy levels. Overcoming stability challenges within the ferromagnetic state is achieved through the manipulation of negative ΔHf within the cubic state. The analysis of the half metallicity character involves an analysis of band structure (BS) and DOS, elucidating its mechanism through PDOS using double exchange model p-d hybridization. The verification of 100% spin polarization is confirmed through factors such as spin polarization and the integer value of the total magnetic moment. Furthermore, the thermoelectric response, as indicated by the ratios of thermal-electrical conductivity and ZT, underscores the promising applications of these compounds in thermoelectric device applications.

First-principles calculations to investigate the structural, electronic, optical, mechanical, and thermodynamic properties of double perovskites Ba2WB′O6 (B′ = Co, Fe, Mn, Ni, and Zn)

We utilized the WIEN2K code within the DFT framework to comprehensively investigate Ba2WBˈO6 (Bˈ = Mn, Fe, Co, Ni, Zn) double perovskite compounds. Structural stability, assessed by Goldsmith's tolerance factor (tG), revealed values close to unity, indicative of stable cubic perovskite structures. The Birch-Murnaghan's equation of state optimization determined ground states, unveiling trends in lattice constant (a0) and bulk modulus (B) for different cations. Structural and phonon stability were confirmed by negative energy formation and real frequencies in phonon calculations. DFPT results affirmed the thermodynamic stability of all compounds. Electronic band structure calculations identified Ba2WMnO6 and Ba2WNiO6 as conductors, while Ba2WCoO6 and Ba2WZnO6 were insulators with 3.7 eV and 3.8 eV band gaps, respectively. Ba2WFeO6 demonstrated semiconducting properties with a 2.37 eV band gap. Density of States (DOS) analysis supported the electronic band structure. Optical conductivity analysis revealed increasing values at higher energy ranges, followed by gradual decreases, differing between conductors and insulators. Absorption coefficient indicated potential suitability for optoelectronic devices, and refractive index analysis highlighted trends in material transparency. To understand fundamental properties, thermodynamic characteristics (thermal expansion coefficient, heat capacities, Debye temperature) were analyzed across a wide pressure (0–30 GPa) and temperature (0–1600 K) range.

Structural, optoelectronic, thermal and transport properties of hybrid perovskite (EAGeCl3) material

Hybrid halide perovskites are emerging as an encouraging option for the fabrication of solar systems. Ethyl-ammonium-based hybrid halide perovskites offer amazing qualities such as reduced bandgap, increased structure stability, and less toxicity. Properties like structural; electrical; optical; and thermoelectric of the material ethyl ammonium germanium chloride are calculated using density functional theory (DFT) simulation code WIEN2K and calculated the optimized structure; density of states; and band structure of EAGeCl3 using exchange-correlation potential KTB-mBJ, establishing it as a direct bandgap semiconductor. Several optical properties such as dielectric function; absorption coefficient; and refractive index over a photon energy spectrum over the range of 0 to 7 eV have also been calculated. In addition, transport coefficients also calculated dependent on concentration of charge carriers, the chemical potential, and temperature at which the material is operating. The findings emphasize the extraordinary properties of EAGeCl3, which has a high ability to absorb electromagnetic radiation, such as light, with a high efficiency, superior compound’s ability to generate an electric potential in response to temperature, among additional benefits. These discoveries confirm its suitability as an affordable material for use in photovoltaic devices, contributing to the resolution of environmental concerns.

Structural Analysis, Characterization, and First-Principles Calculations of Bismuth Tellurium Oxides, Bi6Te2O15

A single crystal of Bi6Te2O15 was obtained from the melt of the solid-state reaction of Bi2O3 and TeO3. Bi6Te2O15 crystallizes in the Pnma space group (No. 62) and exhibits a three-dimensional network structure with a =10.5831(12) Å, b = 22.694(3) Å, c = 5.3843(6) Å, α = β = γ = 90°, V = 1293.2(3) Å3, and Z = 4. The structure was determined using single-crystal X-ray diffraction. An asymmetric unit in the unit cell, Bi3Te1O7.5, uniquely composed of four Bi3+ sites, one Te6+ site, and nine O2− sites, was solved and refined. As a bulk phase, Bi6Te2O15 was also synthesized and characterized using powder X-ray diffraction (XRD), infrared (FT-IR) spectrometry, and the thermogravimetric analysis (TGA) method. Through bond valence sum (BVS) calculations from the single crystal structure, Bi and Te cations have +3 and +6 oxidation numbers, respectively. Each Bi3+ cation forms a square pyramidal structure with five O2− anions, and a single Te6+ cation forms a six-coordinated octahedral structure with O2− anions. Since the lone-pair electron (Lp) of the square pyramidal structure, [BiO5]7−, where the Bi+ cation occupies the center of the square base plane, exists in the opposite direction of the square plane, the asymmetric environments of all four Bi3+ cations were analyzed and explored by determining the local dipole moments. In addition, to determine the extent of bond strain and distortion in the unit cell, which is attributed to the asymmetric environments of the Bi3+ and Te6+ cations in Bi6Te2O15, bond strain index (BSI) and global instability index (GII) were also calculated. We also investigated the structural, electronic, and optical properties of the structure of Bi6Te2O15 using the full potential linear augmented plane wave (FP-LAPW) method and the density functional theory (DFT) with WIEN2k code. In order to study the ground state properties of Bi6Te2O15, the theoretical total energies were calculated as a function of reduced volumes and then fitted with the Birch–Murnaghan equation of state (EOS). The band gap energy within the modified Becke–Johnson potential with Tran–Blaha parameterization (TB-mBJ) revealed a value of 3.36 eV, which was higher than the experimental value of 3.29 eV. To explore the optical properties of Bi6Te2O15, the real and imaginary parts of the dielectric function, refraction index, optical absorption coefficient, reflectivity, the real part of the optical conductivity extinction function, and the energy loss function were also calculated.

A comparative study of physical and thermoelectrical characteristics of the new full‐Heusler alloys Ag2TiGa and Ag2VGa with ab initio calculations

AbstractThis paper will focus on the comparative study of the structural, electronic, magnetic, optical, and thermoelectric properties of the two Heusler systems Ag2TiGa and Ag2VGa in the inverse L21 Hg2CuTi structure. Using the density functional theory‐based wien2k code, which implements the computational methods used in this study, namely GGA, GGA‐mBJ, GGA + U, and GGA + SOC (spin‐orbit coupling). The band structures show that all two structures studied are metallic. The spin density of states of Ag2VGa has evident spin splitting near the Fermi level, and the total magnetic moment of the Ag2VGa structure is 2.19 μB, which indicates that Ag2VGa is magnetic. The full‐Heusler Ag2VGa material can be used as spintronic materials due to their high spin polarization (about 50%). While Ag2TiGa has low polarization so it is bad electronically, but better thermoelectrically than Ag2VGa. So, the full‐Heusler Ag2TiGa material may also be considered as a potential candidate for thermoelectric applications at room temperature. Studies of the two new Heusler alloys may provide a theoretical reference for subsequent theoretical research and experimental synthesis of Ag‐based Heusler alloys.

An Ab-initio study on spin gapless semiconducting in novel quaternary heusler alloys RhCoVZ (Z = Al, Ga, and In): Insights into stability, electronic, magnetic, thermoelectric, and optical properties

The stability and half-metallic ferromagnetic properties of recently developed gapless semiconductor alloys, RhCoVZ (Z = Al, Ga, and In), were the subject of investigation in this research study. Three different non-equivalent structural configurations, namely type I, type II, and type III structures, have been examined. Among these compounds, Type I is characterized as the most stable phase in the ferromagnetic order, as opposed to the non-magnetic order. Through calculations of cohesive energies, formation energies, phonon dispersion curves, and elastic constants, we have demonstrated that RhCoVZ (Z = Al, Ga, and In) exhibits thermodynamic stability, as well as dynamic and mechanical. Using modified Becke-Johnson (mBJ) calculations, it has been revealed that RhCoVZ (Z = Al, Ga, and In) are spin gapless semiconductor half-metallic ferromagnets with an indirect bandgap. Additionally, it was observed that the electrons at the Fermi level (EF) are entirely spin-polarized. The total magnetic moment in all three compounds was determined to be an integer value of 2.00 µB per formula, in accordance with the Slater-Pauling rule (Mt = Zt - 24). All the calculations in this study were performed using density functional theory (DFT) based on the full-potential linearized augmented plane wave (FP-LAPW) method, which was implemented in the WIEN2k code. The effective mass of electrons/holes is (0.167/0.385) for RhCoVAl, (0.454/0.322) for RhCoVGa, and (0.604/0.242) for RhCoVIn. The thermoelectric properties of the three compounds were explored using the semi-classical Boltzmann transport theory. It was discovered that all three compounds exhibit high power factors and high Seebeck coefficients, with values reaching up to 1.5 mV/K for RhCoVAl and 1.25 mV/K for RhCoVGa. Based on the results, the highest observed ZT values for RhCoVZ (Z = Al, Ga, and In) are 0.95, 0.97, and 0.93, respectively. The study's findings indicate that these compounds possess stable characteristics, making them promising candidates for various device applications in fields like spintronics, thermoelectricity, shape memory, and spin filters. Furthermore, the investigation of their optical properties, including the dielectric function and absorption coefficient, suggests potential implications for optoelectronic applications. Overall, these materials exhibit diverse and valuable properties, opening up exciting opportunities for future technological advancements in multiple domains.

Holistic Exploration of Structural, Electronic, Magnetic, Transport, Mechanical, and Thermodynamic Characteristics, Including Curie Temperature Analysis.

Through intricate calculations, the density functional theory (DFT) implemented in the Wien2k code was employed to comprehensively investigate a wide range of material characteristics. Our study encompasses an exhaustive analysis of structural stability, electronic properties, magnetic behaviors, transport phenomena, mechanical responses, and thermodynamic profiles of two notable instances of filled Skutterudites, namely, CeNi4P12 and DyCo4Sb12, which have been thoroughly explored. These computations were performed using the WIEN 2K code, combining local orbitals and the full-potential linearized augmented plane-wave approach. The findings provided insight into the wide range of properties of these materials. In this methodology, the exchange-correlation potential relies on the local-density approximation. We conducted the calculations with and without incorporating spin-orbit interactions. The results obtained provide information about the lattice constant, bulk modulus, and pressure derivative. The stability, as indicated by the P-V graphical plot, suggests that there are no structural phase transitions from the cubic symmetry structure. Notably, our work includes an examination of Curie temperatures, which are pivotal in understanding magnetic phase transitions. The validated elastic properties further support the material's stability and corroborate its ductile nature. These alloys should be considered for spintronic and thermoelectric applications due to their estimated transport characteristics and the observed ductile nature. To enhance our understanding of the thermal stability of antimony-based compounds, we have made reliable estimations of the thermophysical characteristics. By integrating theoretical insights with practical implications, we bridge the gap between fundamental understanding and material design applications. Using DFT in the Wien2k framework, we discover connections and patterns among different properties, showing how to create materials with specific functions and better performance. This approach not only advances our fundamental comprehension of materials but also promises innovation across various technological domains.

Ab-initio calculation of halogen elements effect on the behavior of new double perovskite Cs2InSbX6 (X = F, Cl, Br, I): 1st part structural and optoelectronic properties

In recent years, there has been a growing fascination with lead-free perovskite materials, particularly in the realms of solar energy and photonics. It is imperative to conduct comprehensive theoretical investigations of these materials to effectively guide experimental pursuits. In this research, we harnessed the power of density functional theory (DFT) calculations, employing the Wien2k code, to delve into the distinctive characteristics of double-perovskite halides Cs2InSbX6 (X = F, Cl, Br, I). The viability and stability of their cubic structures were meticulously assessed, taking into consideration essential metrics such as the tolerance factor, octahedral factor and formation energy. Notably, the pronounced influence of spin–orbit coupling necessitated gap energy adjustments, achieved through a dual-pronged approach utilizing the generalized Perdew–Burke–Ernzerhof gradient approximation (PBE-GGA) and the modified Becke-Johnson (mBJ) exchange potential. The intricacies of band structure and state density were scrutinized using the GGA + mBJ method. The comprehensive findings elucidate that these compounds manifest fundamental electronic bandgaps spanning a range from 0.26 to 2.67 eV. Furthermore, they exhibit remarkably low carrier effective masses and a substantial degree of band dispersion. Of significance is the profound influence of halogen atom substitutions on their optical properties. Notably, a high absorption coefficient in the ultraviolet spectrum and the presence of a negative real dielectric function provide strong evidence for the adoption of metallic properties within a specific energy range. These compelling outcomes underscore the potential of these materials as highly promising candidates for a diverse array of photonic applications.

Ab initio studies of newly proposed zirconium based novel combinations of hydride perovskites ZrXH3 (X = Zn, Cd) as hydrogen storage applications

Using the WIEN2k code, first-principles simulations of ZrXH3 (X = Zn, Cd) hydride perovskites are performed to determine their hydrogen storage properties. The purpose of this study is to investigate their structural, optoelectronic, hydrogen storage, mechanical and thermoelectric properties. The structural analysis demonstrates their stability through the heat of formation along with desorption temperature and shows that these compositions belong to the orthorhombic space group Cmcm (no.63). The band structure and density of states are estimated for electronic characteristics, indicating the metallic nature of both compositions. Analysis of elastic properties such as elastic constants, Pugh’s ratio, bulk modulus, Poisson’s ratio, and anisotropy factor are explored to determine the mechanical stability of these compositions and demonstrate their suitability as a transport medium in hydrogen storage systems even at higher pressure. To study the optical behavior of the perovskites under consideration for hydrogen storage applications, the dielectric parameters, dielectric constants, refractive index, optical conductivity, absorptivity, and energy loss function are studied. The present paper represents the initial theoretical effort toward future exploration of these materials for hydrogen storage applications.

Exploring the potential of inorganic cubic halide perovskites RbSrM3 (M=Cl, Br) for advanced optoelectronic applications: A DFT study

Halide perovskites, being a large family attained researchers focus for multiple targets because of their outstanding properties and flexible chemistry. In this study, density functional theory (DFT) based on WIEN2K code were utilized, to thoroughly explore the structural, electronic, optical, and mechanical properties of inorganic cubic halide perovskites, i.e.; RbSrM3 (M = Cl, Br) for optoelectronic applications. Variation in the lattice parameters and unit cell volume were observed, as a result of halogen atom substitution from Cl with Br. Subsequently, the electronic characteristics certify the direct bandgap nature, with bandgap values of 7.73 eV for RbSrCl3 and 6.79 eV for RbSrBr3, respectively. Optical properties proposed the high optical absorption, high conductivity, and low reflectivity. Further analysis into the mechanical properties, including bulk modulus (B), shear modulus (G), young modulus (E), anisotropic factor (A), Poison’s ratio (ν), and Pugh’s ratio (B/G), comply the near ductility, stiffness, and elastically anisotropic behavior, confirmed the stability and reliability of the designed compound. Debye temperature (θD), showing high capability to withstand against heat produced by lattice vibrations, further associated the thermodynamic stability that support the formation energy calculations. Based on the findings, it is confidently suggested that investigated halide perovskite materials i.e.; RbSrM3 (M = Cl, Br), are promising candidates for next-generation photodetectors and optoelectronic devices.

First principle insight on optoelectronic and transport characteristics of lead-free inorganic double perovskites Rb2KTlX6 (X = Cl, Br) for solar cell applications

The toxicity and instability of lead-based perovskites have been replaced with newly investigated stable lead-free inorganic perovskites. The current study included the comprehensive analysis of electronic behavior, elastic, optical, and transport characteristics of lead-free inorganic double perovskites (DPs) Rb2KTlX6 (X = Cl, Br) halides for possible uses. These physical characteristics were revealed using density functional theory (DFT) based Wien2k code. Using the energy optimization process, we have computed structural parameters comparable to existing data using generalized gradient approximation (PBEsol-GGA). In addition, the elastic parameters, formation energy (−1.94 eV and −1.39 eV), and tolerance factor (0.98 and 0.97) endorsed the cubic stability of both halides. Further, we employed modified Becke-Johnson (mBJ) potential to an accurate value of direct bandgaps of both halides reveal that changing the anions from Cl to Br leads to significant adjustment in the band gap, transitioning from the visible to the IR spectrum, with energy levels ranging from 2.08 to 1.2 eV. Our calculated results of optical parameters indicate that both halides with remarkable optoelectronic working due to low reflectivity, high optical absorption, and conductivity. The study reveals that electronic transport factors are associated with temperature due to small bandgap of the materials. The observed figure of merit near unity indicates the semiconducting behavior of these materials that can be useful in thermoelectric tools.

Role of 4d electrons in room temperature ferromagnetism, and thermoelectric properties of Sr2CrXO6 (X = Nb, Mo) for spintronic applications

The spintronic is an emerging technology which controls the properties of multifactional devices with spin of electrons. In present manuscript, Wien2k and Boltz Trap codes are used to explore electronic, magnetic, and thermoelectric characteristics of Sr2CrXO6 (X = Nb, Mo) double perovskites (DPs). The evaluation of energies released in paramagnetic (PM), antiferromagnetic (AFM), and ferromagnetic (FM) states assure the stability of FM states. Both the negative formation energy and the tolerance factor confirm structural and thermodynamic stability in FM states. The 100 % spin polarization was confirmed by both integer values of magnetic moment (MM) and the spin polarization factor. The values of exchange energy, double exchange model, hybridization of p-d states, and exchange constants are calculated to explore the nature of ferromagnetism and spin functionality. The effect of thermoelectric parameters on spin of electrons and thermoelectric performance are elaborated by thermal to electrical conductivity ratio, Seebeck coefficient and power factor.

Vibrational and transport phenomenon in Cs2CdZnCl6 double perovskite: A DFT study

This study aims to study of physical parameters of the Cs2CdZnCl6 double perovskite compound implementing a full-potential linearized augmented plane wave (FP-LAPW) technique and Boltzmann transport equation within the framework of density functional theory (DFT) as carried out in the WIEN2k code. The Birch Murnaghan equation of state (EOS) and the generalized gradient approximation (GGA) were both used in the structural analysis, resulting in the stable phase for Cs2CdZnCl6 double perovskite. The compound is found to be semiconductor in nature with band gap of 3.971 eV. Strong hybridization between the Cd-3d and Zn-5d orbitals was seen in the DOS data, confirming the ionic character due to the relative abundances of the two states. Thermodynamic features have been computed for temperature ranges (0−1200K) and pressure ranges of around 0–30 GPa, In regard to thermoelectric properties, calculations have been made for temperature, chemical potential, and charge carrier concentrations. Positive values of the Seebeck coefficient characterize the p-type nature of Cs2CdZnCl6. The highest Seebeck coefficient ever recorded was 235.41 mV/K at 130 K. According to calculations, the maximum ZT value at 600 K is 0.65, which raises the possibility that Cs2CdZnCl6 is a high-performance thermoelectric material.

A2LiGaI6 (A = Cs, Rb): New lead-free and direct bandgap halide double perovskites for IR application

Recently, all inorganic double perovskites have drawn a lot of interest as promising solar materials. The optical, structural, thermoelectric, electronic, and mechanical properties of double halide perovskites A2LiGaI6 (A = Cs, Rb) are explored via first-principles calculations with the WIEN2k code, using GGA PBEsol and TB-mBJ potentials. The majority of perovskite materials utilized in the highest-performing solar cells have bandgaps ranging between 1.48 and 1.62 eV. The compounds A2LiGaI6 (A = Cs, Rb) have a direct bandgap of 1.51 eV and 1.55 eV, respectively, and are expected to be useful in solar cells. The optical study shows that there are large absorption bands in the visible region, as determined by the dielectric constant, absorption, and other dependent factors. Their potential for use in solar cells is increased by their absorption in the visible part. The BoltzTraP code has been used to perform thermoelectric studies to assess the electrical, thermal conductivities, and Seebeck coefficient. They are important for construction of thermoelectric generators that harvest heat energy because of their high figure of merit and incredibly low thermal conductivity of lattice at ambient temperature. Furthermore, by examining the spectroscopic limit maximum efficiency, up to 30 % efficiency is predicted for both compositions, which paves the way for the applicability of them in solar energy conversion.

Structural, elastic, electronic, optical and thermoelectric properties of metal based ternary chalcopyrite semiconductor for photovoltaic application: First-principles studies

In this article, the physical properties of XCrS2 (X = Zn, Cd, and Hg) are studied by Density Functional Theory (DFT) using Wien2K code. Stability, along with certain parameters of the crystal structures of the compounds, was evaluated based on PBE-GGA. Mechanical properties reveal that the studied compounds XCrS2 (X = Zn, Cd) are stable, and their elastic constants and Paugh’s ratio exhibit that ZnCrS2 is brittle, whereas CdCrS2 is ductile in nature. Furthermore, HgCrS2 does not satisfy the Born stability criteria. The modified Becke-Johnson (mBJ) potential was used to improve the band gap properties and results depict that the XCrS2 (X = Zn, Cd) compounds have 1.30 and 1.27 eV direct band gaps, respectively. Thermoelectric properties exhibit the highest optical conductivity with energy loss and the strongest absorption is observed for CdCrS2 in the visible region, which also has the best photovoltaic activity. The higher obsorption nature makes this material a good candidate for solar devices. The electrical and thermal conductivity increase with an increase in temperature, and ZnCrS2 has a greater ZT compared to CdCrS2.

First-principles calculations to investigate structural, electronic, optical, elastic and thermodynamic properties of Yb3Q5 (Q=Ge, Si) for energy applications

From the first-principles DFT calculations, we explore the optoelectronic and thermoelectric properties of Yb3Q5 (Q= Ge, Si). The ground state properties of crystalline materials can precisely be estimated using the FP-LAPW technique implemented in the WIEN2K code. It can be determined that the compounds under consideration are metallic based on their band structures. Fermi surfaces of Yb3Q5 (Q= Ge, Si) are also calculated to investigate the electronic conductivity of these materials at the Fermi level. The phenomenon of absorption and dispersion of incident photons can be explained using obtained dielectric function ε(ω) for Yb3Q5 (Q= Ge, Si) compounds. The infrared (IR) region is where Yb3Q5 (Q= Ge, Si) compounds absorb most light packets, however, their absorption in the visible region is also not negligible. These materials are also potential candidates for antireflecting coatings in the upper UV region. Yb3Q5 (Q= Ge, Si) are brittle compounds as their B/G values are less than 1.75. Thermodynamic parameters show that these compounds are thermodynamically stable.

Exploring structural, electronic, magnetic, and optical response of GaN-X (X=Sr, ba, cs, mg) materials for optoelectronic applications

This research explores the structural, electronic, magnetic, and optical properties of GaN-X (X = Sr, Ba, Cs, Mg) materials. First principle calculations based on full potential linearized augmented plane wave (FP-LAPW) method is executed in Wien2k code. PBE-GGA approximation is used to approximate exchange-correlation functional. Sr 3d-states, Ba 5p-states, Cs 5p-states, and Mg 2p-states help in improving electronic properties. The magnetic character of the proposed materials is revealed with net magnetic moment values of, 2.9639 μB, 2.3316 μB, 3.4179 μB, and 3.1697 μB, respectively. Optical absorption shows blueshift for Ba@GaN and Mg@GaN while Sr@GaN and Cs@GaN spectra show redshift. Absorption and conductivity are enhanced in the UV region, along with decrease in reflectivity. Optical response of proposed materials illustrate to make use of these materials for production of high energy UV optoelectronics, photonics, memory, spintronics and photovoltaic devices.

Influence of chalcogenides on the optoelectrical properties of semiconductor ternary alloys Zn₀.₉₅Cd₀.₀₅X (X=S, Se and Te): A DFT study

In this article comprehensive study of the thermoelectric and optical properties of the Zn₀.₉₅Cd₀.₀₅X (X = S, Se and Te) by using first principle DFT calculation incorporating the Wien2k code, has been considered. Firstly, we determined the optimized structural parameters, comprising of the atomic coordinates. All the properties like the energy band structure, densities of electronic states and energy dependence of the optical functions were figured out. We found the decrease in their band gaps (3.5 eV, 3.0 eV and 1.9 eV respectively) as we replace S by Se and Te, respectively. We found that they are having direct band gap having transition along Γ- Γ symmetry point. The electronic interband transitions accountable in the optical spectra were specified. In parallel the standard Boltzmann transport theory were used to calculate the thermoelectric parameters, including Seebeck coefficient, electrical and thermal conductivities and figure of merit. In response we found that the investigated compounds are potential candidates for thermoelectric applications.