Full-potential Augmented Plane Wave Research Articles

Optoelectronic and thermodynamic properties of the Yttrium filled skutterudite YFe4P12

In this work, we sought to understand the structural, electronic, optical, and thermodynamic properties of the compound YFe4P12 using the full-potential and linear augmented plane-wave method (FP-LAPW) based on density functional theory (DFT), our calculation of the lattice parameter of this compound YFe4P12 is reasonably in good agreement with the experimental results. Calculations carried out on the electronic band structure showed that the YFe4P12 compound is classified as a direct-gap Half- half-metallic in the minority spins. Moreover, optical properties, such as the optical absorption coefficient, real and imaginary parts of the dielectric function, optical conductivity, refractive index, and optical reflectivity have been studied. The effects of pressure and temperature on the lattice parameter, heat capacities, coefficients of thermal expansion, entropy, and Debye temperature were explored using the quasi-harmonic Debye model.

Theoretical study of optoelectronic, elastic and mechanical properties of gallium modified barium titanate (Ba1-xGaxTiO3) perovskite ceramics by DFT

In this report, we study the gallium modified Barium titanate (Ga-BTO) Ba1-xGaxTiO3 with (x = 50 %) perovskite ceramics, which have not been synthesized experimentally to date. The density functional theory-based full potential linear augmented plane wave has been employed to determine the optoelectronic, elastic, and mechanical properties of pure and modified BaTiO3. Completely relaxed 2 × 2× 2 of primitive five atoms’ cells has been used for calculations. A large cut-off energy of 120 Ry has been used to eliminate the basics of plane wave-indicating wave functions. The influence of substitution of Ga on electronic structure and optical parameters such as reflectivity, refractivity, dielectric function, optical conductivity, extinction, and absorption coefficients are analyzed and elucidated with TDOS and PDOS. The Ga modified BTO manifests a forbidden energy gap of 1.84 eV. The static dielectric constant Ɛ1(o) has values of 8.8 and 100 for pure and modified compounds respectively. Ga dopant improved the polarizing power of BTO and for the doped BTO imaginary part, Ɛ2(ω)showed a prominent peak located at 3.9 eV. The optical properties show that perovskite compound substituted with Ga is a good absorber in the ultraviolet region and the modified material has a small value of reflectivity and static refractive index 12.2. The general profiles of optical spectra of modified BaTiO3 display highly desirable features like the prominent peaks of optical conductivity obtained at 4.2 and 5.8 eV for modified BTO that make it a promising candidate for optoelectronic and spintronics. Ga-modified BTO has higher ductility, modulus (169.96 GPa), and anisotropy (2.949) than pure BTO found by analyzing their elastic and mechanical properties.

Investigating the structural, electronic, and magnetic properties of Cd1-xVxTe: Insights from First-Principles calculations

In our study, we aim to investigate the structural, electronic, and magnetic properties of CdVTe, a diluted magnetic semiconductor with a Cadmium telluride (CdTe) structure. To achieve this, we employ the full potential linear augmented plane wave method implemented in the CASTEP code, which allows us to accurately simulate the behavior of the system. To describe the electronic exchange and correlation effects, we adopt the generalized gradient approximation (GGA) within the density functional theory (DFT) framework. This choice of methodology ensures reliable and accurate calculations of the electronic and magnetic properties of Cd1-xVxTe. Our results reveal that the substitution of Vanadium (V) into the Cadmium (Cd) site of the CdTe lattice does not alter the zinc blende crystal structure, demonstrating the stability and structural integrity of the system. Furthermore, our calculations demonstrate that the introduction of Vanadium impurities leads to spin polarization within the material, resulting in the emergence of a magnetic moment. Notably, we find that a Vanadium concentration of approximately x≈0.12 exhibits the strongest magnetic properties, characterized by a significant magnetic moment. These findings provide valuable insights into the behavior and potential applications of CdVTe as a diluted magnetic semiconductor, shedding light on the interplay between structural, electronic, and magnetic properties in this material.

First-principles investigation of structural electronic magnetic and thermodynamic properties of CdS alloyed with Co transition metal

This research work investigates the structural, electronic, and magnetic properties of Cd1–xCoxS compounds. The supercells with 16 atoms have been studied by substituting a Cd atom with a Co atom in the cubic unit cell CdS from x = 0 to x = 1 in a Zinc-Blende structure based on the first principles of spin-polarized density functional theory as implemented in the WIEN2k code. The full potential augmented plane wave method FP-LAPW (Full potential linear augmented plane wave) was used in this study to evaluate the structural properties of the compounds, the exchange–correlation term is based on the PBE-GGA (Perdew–Burke–Ernzerhof generalized gradient approximation). For other properties, such as electronic structures, densities of states, and magnetic properties, the TB-mbj GGA (Tight Binding modified Becke–Johnson) exchange potential approximation is utilized. In addition to these properties, the thermodynamic properties were added advantage to clarify their comportment as temperature variation. The analysis of the density of spin-polarized states showed the ferromagnetic character with a from x = 0.125 to x = 0.875. The calculated total magnetic moments of Cd1–xCoxS are addressed concerning the change in lattice parameters. To track the shift brought on by adding Co, we ran our calculationsfrom x = 0.125 to x = 0.875 for Cd1–xCoxS compounds. Hence, the negative energyformation indicates that our compound can be made experimentally. The material may be used for solar cell applications. In summary, our findings represent a guide for future research. The findings of this work might provide useful direction for the usage of this alloy system in a variety of device applications, For example in high-efficiency tandem solar cells, magnetic sensors, and photoconductive detector applications.

DFT study of energetics and optoelectronics properties of B, C, and N binary and ternary honeycomb structures

Using the Full Potential Linear Augmented Plane Wave and the pseudo-potential method based on the Density Functional Theory, we investigate the physical properties of two-dimensional (2D) boron nitride, carbon nitride, and boron carbide as well as their ternary system boron carbon nitride (BCN). The structural and optoelectronic properties are determined and discussed in detail with available theoretical and experimental results. We show that the studied physical properties are influenced and tunable by atom concentration. A high concentration of nitrogen (> 50%) disturbs the honeycomb structure of binary and ternary alloys. Additionally, the optoelectronic properties are very sensitive to the amount of boron and nitrogen atoms. The zero bandgap is only conserved for B3C12N3 and B6C6N6 ternary systems. A large bandgap was observed for B9N9 (∼3.9 eV) and a moderate one for B6N12 and B3N15 (∼2 eV). The coexistence of boron, carbon, and nitrogen atoms with different concentrations has important optical properties as they can absorb light in all spectra. However, they have more active absorption in the ultraviolet than visible regions. It is more interesting to use ternary BCN than binary or pristine alloys with tunable optoelectric properties, by varying the nitrogen content in nanodevices.

First principle studies on structural, elastic, electronic, optical, and thermoelectric properties of new perovskite TlTaO3: For renewable energy applications.

The structural, optoelectronics, and transport properties of TlTaO3 compounds were determined utilizing the full potential augmented plane wave approach using first-principle method. We have considered the generalized gradient approximation for structural optimization and modified Becke-Johnson for electronic properties. The electronic properties reveal that the studied TlTaO3 possesses direct bandgap of magnitude 1.52 eV. Between 0 and 12 eV, optical spectra calculations are made, taking into account the real and imaginary parts of the dielectric function, refractive index, and loss function. The transport properties are estimated considering Boltzmann transport theory. The Seebeck coefficient, electrical conductivity, thermal conductivity, and power factor are all assessed using the Boltzmann transport theory. The optimized thermoelectric response of the examined TlTaO3 is produced by the improved carrier mobility, which also improves the thermoelectric efficiency of the TlTaO3. The obtained results will act as a theoretical road map for upcoming experimental and commercial TlTaO3 applications.

A computational insight into the Zintl SZr2N2 and BaAg2S2 phases for optoelectronic thermoelectric applications

The physical characteristics of SZr2N2 and BaAg2S2 Zintl phases have been explored by utilizing the full-potential augmented plane wave (FP-LAPW) method with the combination of modified Becke-Johnson (mBJ) approximation. The negative formation energies and phonon modes with positive frequencies endorsed the stability of both compounds. The electronic band profile reveals a bandgap of 1.18 eV for SZr2N2 and 2.15 eV for BaAg2S2. The optical characteristics are also calculated. The absorption of light for the studied compounds falls in the ultra-violet region, which shows their possibility to be employed as UV-rays absorbers. A large optical conductivity and low energy loss is also seen for both materials on UV region. The efficiency of temperature-dependent thermoelectric properties increases with the temperature rise, as calculated with the BoltzTraP code. The high electrical with low thermal conductivities and maximum Seebeck coefficient is witnessed for both materials. The large ZT values of 0.75 and 0.80 are achieved for SZr2N2 and BaAg2S2, respectively. All calculated transport parameters indicate the opportunity of using the studied compounds for thermoelectric applications.

Electronic Structure and Optical Properties of Inorganic Pm3m and Pnma CsPbX3 (X = Cl, Br, I) Perovskite: A Theoretical Understanding from Density Functional Theory Calculations.

In this study, we investigated the optoelectronic properties of cubic (Pm3m) and orthorhombic (Pnma) CsPbX3 (X = I, Br, and Cl). We utilized the full potential linear augmented plane wave method, which is implemented in the WIEN2k code, to facilitate the investigation. Different exchange potentials were used to analyze the optoelectronic behavior using the available density functional theory methods. Our findings revealed that CsPbX3 perovskites display direct band gaps at the R and Г points for cubic (Pm3m) and orthorhombic (Pnma) structures, respectively. Among the exchange potentials, the mBJ-GGA method provided the most accurate results. These outcomes concurred with the experimental results. In both Pm3m and Pnma structures, interesting changes were observed when iodide (I) was replaced with bromine (Br) and then chlorine (Cl). The direct band gap at the R and Г points shifted to higher energy levels. Similarly, when I was replaced with Br and Cl, there was a noticeable decrease in the absorption coefficient, dielectric constants, refractive index, and reflectivity, in addition to a band gap shift to higher energy levels.

Ab-initio investigations for structural, optoelectronic and thermoelectric properties of Li2BeXSe4 (X = Ge, Si, Sn) compounds

Motivated by photovoltaic activities, we study certain aspects of the stannite structure (ST) of the Li2BeXSe4 (X = Ge, Si, Sn) compounds using the full potential augmented plane wave approach implemented in the Wien2k code. Concretely, we use the generalized gradient approximation (GGA) and the modified Becke–Johnson exchange potential (mBJ) to evaluate in a precise way, the band gaps, the total and the partial densities, as well as the optical and the thermoelectric properties. Among others, we show that the Li2BeXSe4 (X = Ge, Si, Sn) semiconductors exhibit a direct band gap in the Γ point of the Brillouin Zone (BZ). Furthermore, the optical properties of the three compounds show a strong optical conductivity and a good optical absorption. As a result, we reveal that the proposed materials are suitable for the application in photovoltaic solar cells. Using the BoltzTrap package, we also examine and discuss the thermoelectric properties such as the Seebeck coefficient (S), the electrical conductivity, and the thermal conductivity as a function of the temperature. We find that the Li2BeXSe4 (X = Ge, Si, Sn) compounds exhibit good thermoelectric transport properties, making them a good candidates for clean energy applications.

Reduction of cadmium content in 29 % and 54 % P2O5 phosphoric acid by manganese oxide material birnessite-type Na-MnO2

This paper presents a new approach for the purification of 29% and 54% P2O5 phosphoric acid contaminated with cadmium ions using synthesized lamellar material based on manganese (Na-MnO2). The removal efficiencies of cadmium ions were 35 % and 31 % for 54% and 29% P2O5 phosphoric acid. The kinetic and isotherm studies of cadmium adsorption were performed. After the phosphoric acid purification process, Na-MnO2 material was characterized by XRD, SEM, and TGA-DTA. All the results enable the refinement of the final phase by the Rietveld method. A proposed mechanism of cadmium ion removal by Na-MnO2 was given. The stability of the material was also controlled in the acid medium 29 % and 54 % P2O5. The results confirmed that Na-MnO2 material could be a potential sorbent for the efficient removal of heavy metals from phosphoric acid solutions. This simple process can be further developed and thus opens an avenue in the industrial sector to process larger quantities using high-performance materials based on manganese. Self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and using the FLAPW method (Full potential Linear Augmented Plane Wave), were performed to investigate both the electronic and magnetic properties of materials.

Insight into physical properties of carbon-doped BeSiP2 and BeGeP2 chalcopyrite: An ab initio study

Our present article reports the carbon substitution-driven changes in the behavior of BeSi1-xCxP2 and BeGe1-xCxP2 (x = 0.25 and 0.5) chalcopyrite alloys using the full-potential augmented plane wave plus local orbital (FP-APW + lo) based first-principles calculations. The lattice constants (a and c) of BeSi1-xCxP2 and BeGe1-xCxP2 are shortened, and the bulk moduli are improved as carbon atoms replace Si and Ge atoms. The computed negative formation energy (Ef) indicate adequate thermodynamic stability of the BeSi1-xCxP2 and BeGe1-xCxP2 alloys. The bandgaps pristine BeSiP2 and BeGeP2 computed as 1.84 eV and 1.54 eV, respectively, using the modified Tran-Blaha (TB) Becke Johnson (mBJ) transition potential, matching well to the experimental results. However, the C substitution is found to narrow the bandgap of BeSiP2 and BeGeP2 considerably. Similarly, C substitution is found to reduce electrons' and holes’ effective mass and enhance the absorption coefficient of BeSi1-xCxP2 and BeGe1-xCxP2 alloys up to (α∼105cm−1). Our predictions indicate that the physical properties of BeSiP2 and BeGeP2 chalcopyrite can be modified effectively by replacing C in the Si and Ge sites, which makes them promising for optoelectronic applications.

Theoretical insight on the electronic band structure, mechanical, vibrational and thermodynamic characteristic of antiperovskites RE3InN (RE=Y and La)

The purpose of the current work is to examine the structural, elastic, phonon, and thermodynamic features of antiperovskites RE3InN (RE = Y and La) compounds using the Full potential augmented plane wave method (FP-LAPW) within the framework of density functional theory (DFT). The generalized gradient approximation of Perdew-Burke and Ernzerhof (GGA-PBE) exchange correlation have been considered to optimize the lattice parameters. The elastic properties of the investigated antiperovskite RE3InN (RE = Y and La) compounds has been studied in terms of Young, shear, bulk modulus, Poisson ratio, Debye temperature etc. The Debye temperature for RE3InN (RE = Y and La) compounds are found to be 575 K, 450 K, respectively. The compound La3InN is ductile while Y3InN compound is brittle in nature as evidenced from Cauchy pressure, Pugh ratio etc. La3InN compound is mechanically stable according to elastic property analysis. The electronic properties analysis suggests that the studiedcompounds aremetallic that arises from Y/La-4d/5d states. Additionally, we computed the thermodynamic variables, such as the bulk modulus B, relative volume, heat capacity, thermal expansion, and relative Debye temperature at a range of temperatures (0–1200 K) and pressures (0–40 GPa). The results that have been revealed should be helpful for future antiperovskite synthesis as well as for expanding our understanding of this promising class of antiperovskite-type materials.

Investigations of physical properties of lithium-based chalcopyrite semiconductors: non-toxic materials for photovoltaic applications

The ab-initio calculations have been executed for structural, electronic and optical properties of LiAlTe2, LiGaTe2 and LiInTe2 chalcopyrite structured solids and these calculations are grounded on the principle of density functional theory employed into the full potential augmented plane wave method. The computed lattice constants oscillating from a = 6.257 Å to 6.450 Å and c = 12.044 Å to 12.256 Å for LiXTe2 (X=Al, Ga and In) and also these values consistent with experimentally existed lattice constants. From the study of electronic band-gap, it confirms that these compounds are good semiconductors with direct band-gaps from 2.22 eV, 1.48 eV and 1.61 eV for LiXTe2 (X=Al, Ga and In). The result of optical properties confirms that these chalcopyrite semiconductors can be the fortunate compounds for the photovoltaic applications.

First-principles study for physical properties and stability of Li based chalcopyrite semiconductors: Reliable for green energy sources

In this research study, we have been performed the first principles calculation for physical properties likewise structural, electronic, optical and mechanical properties of the lithium gallium chalcopyrites LiGaX2 (X= S, Se). We have used two exchange correlation potentials one is full potential augmented plane wave method (FP-LAPW) and second is pseudo-potential method. The reported lattice parameters in this work ranging from a = b = 5.28 Å to 5.82 Å and c = 10.11 Å to 11.25 Å and found that these materials have direct band-gap 4.41 eV for LiGaS2 and 2.90 eV for LiGaSe2­. Refractive indexes n(ω) is 2.1 and 2.3 respectively for these compounds. The study of optical and elastic properties for these materials ensures that these show the anisotropic behaviour and ductile in nature.

Insight into the electronic structure, magnetic, and thermoelectric properties of transition metal pnictides KCr2L2 (K= Ca, Sr; L = P, As): As substitute source for renewing energy

In this study, we have investigated the electronic structure, magnetic and thermoelectric properties of the antiferromagnetic (A-AFM) phase for ternary KCr2L2 (K= Ca, Sr; L = P, As) compounds using the framework of full-potential augmented plane wave method within the generalized gradient (PBE-GGA) approximations. We determined that the presence of the A-AFM phase is more favorable among the possible spin phases at their relaxed lattice parameters. Based on the stable phase, we found that both Cr atoms are well modulated in AFM phase. Furthermore, we have investigated the thermoelectric properties for all investigated compounds from 50 K to 800 K. Our calculations suggest the SrCr2As2 and SrCr2P2 compound can obtain high figure of merit values ∼1 with optimized carrier concentration at lower temperature, indicating the strontium based compounds are promising candidate for low-temperature thermoelectric device. In all, our calculations discover the novel ternary KCr2L2 (K= Ca, Sr; L = P, As) compounds with promising physical properties for potential spintronics and magnetic application.

Electronic and optical properties of quaternary selenides for optoelectronic applications: Insights from DFT+U‐computations

AbstractThe optical properties, electronic charge density, electronic structure of the new layered selenides materials, BaGdCuSe3, CsUCuSe3, CsZrCuSe3, and CsGdZnSe3 compounds have been calculated by using the full potential and linear augmented plane wave (FP‐LAPW) methods as applied in the WIEN2k package, which is based on the density functional theory. The ALnMSe3 compound's structure of these was (A = Cs, Ba; Ln = Zr, Gd, U; M = Cu, Zn) is composed of (n = 1, 2) layers, which might be separated by A atoms. It is to be observed that there is strong hybridization between the s, p, and d states of Zr, Gd, and Cu atoms. Around the gadolinium atom, the charge density contours are completely circular, but the Gadolinium “Gd” atom shows an ionic nature. To calculate the refractive index, we used Kramer's Kronig correlations with the imaginary part dielectric function. The decrease in the refractive index is due to the lack of probability for direct excitation of the electrons, resulting in a loss of energy. The value of the static refractive index for all reference compounds is about 1.75–2.25, which is indication that the material used in optoelectronic devices.

Investigation of electronic structure, magnetic stability, spin coupling, and thermodynamic properties of novel antiferromagnets XMn2Y2 (X = Ca, Sr; Y = P, As)

In the present work, the structural, electronic, magnetic, and thermodynamic properties of ternary compounds of composition XMn2Y2 (X = Ca, Sr; Y = P, As) are reported. The calculations are performed using the full potential augmented plane wave method (FP-APW) within the framework of density functional theory (DFT) as integrated with the WIEN2k code. The volume optimization is performed for different spin configurations to obtain the optimized unit cell structure, using the minimum energy considerations. It is found that the studied systems favor the antiferromagnetic (AFM) structure. Calculated structural parameters are in good agreement with the existing data. Based on their band structures and density of states (DOS), CaMn2P2, SrMn2P2, and SrMn2As2 have a metallic character, while CaMn2As2 is a semiconductor with a narrow band gap of 0.1161 eV on using GGA and as metallic when GGA+U is employed. The density of states diagrams show that the Mn-3d state contributes majorly to the valence band and the lower part of the conduction band. From stable geometries of XMn2Y2 compounds, it is evident that the Mn atoms are coupled antiferromagnetically in all the compounds. The large value of TC for CaMn2As2 shows strong correspondence among the magnetic atoms. Owing to their suitable magnetic characteristics, these compounds can be used in applications such as Colossal magnetoresistance (CMR) or Giant magnetoresistance (GMR), single-molecule magnets, read heads, spin filters, spin valves, magnetic sensors, and in spintronics applications. Furthermore, temperature and pressure dependence of thermodynamic properties of these materials have been examined in the ranges (0–800 K) and (0–18 GPa), respectively.

First-principles investigation of electronic and optical properties of Fe doped in CsBrO3 for enhanced photocatalytic hydrogen production

Self-consistent ab initio calculations carried out using full potential augmented plane wave (FP-LAPW) method were performed to study the electronic, optical and photocatalytic properties of CsBrO3 and Fe doped CsBrO3. Ground state and formation energy for CsBrO3-perovskite are calculated and analyzed. The magnetic moment of Cs, Br, Fe and O are calculated in CsBrO3 and CsBr0.34Fe0.66O3. The band structure, total and partial density of states (DOS) diagrams are discussed.The CsBrO3 have semiconductor character with a wide direct gap. The value of gap energy is 4.24 eV of CsBrO3. Fe doped in CsBrO3 lead to band gap narrowing 1.02 eV for spin up and 1.434 eV for spin dn , which enhances the visible light catalytic activity. The conduction band minimum (CBM) and valence band maximum (VBM) potentials vs. normal hydrogen electrode (NHE) are calculated and analyzed. The general profiles of the optical spectra and the optical properties, including the real and imaginary part of dielectric function, reflectivity, absorption and optical conductivity are discussed. Our results predict that Fe doped CsBrO3 is a promising visible light photo-catalyst for hydrogen production by water splitting.

Temperature induced phase transformation in Co

Temperature dependent phase transformation behavior in cobalt from hexagonal close-packed (hcp) to face centered cubic (fcc) has been found to be contradictory to that reported earlier. It is found that hcp phase stabilizes at both low and high temperature (sim 873 K) while fcc phase is stabilized at sim 500 K. At 298 K, hcp Co has been found to be predominant (sim 70%) where hcp magnetic phase is sim 60%. At 973 K, hcp phase is again predominant (sim 73%), but it is mainly the non-magnetic phase (sim 67%). Contrary to present results, it was found earlier that fcc phase was stabilized at high temperature and hcp to fcc transformation occured at sim 700 K. Present results from perturbed angular correlation measurements, therefore, requires a new theoretical interpretation for Co phase transformation. From present measurements, hyperfine magnetic fields in Co at room temperature for the hcp and fcc phases have been found to be 18.7(6) and 12.8(3) T, much lower than earlier reported results. The hyperfine magnetic fields at ^{181}Ta impurity atom have been calculated by density functional theory (DFT) employing the full potential (linearized) augmented plane wave method (FP-LAPW). Present calculated results for both hcp and fcc phases corroborate our experimental results.

High energy Compton scattering, electronic structure and optical response of zirconium substituted lead titanate

The electron momentum densities of PbTi1-xZrxO3 (x = 0, 0.4 and 1) measured using high energy 137Cs Compton spectrometer are reported. To validate the measurements, theoretical Compton profiles (CPs) and electronic structure of PbTi1-xZrxO3 (x = 0, 0.4 and 1) are computed using the linear combination of atomic orbitals (LCAO) method. Differences between experimental and theoretical CPs unveil that the hybrid scheme (WC1LYP) is more applicable to account exchange and correlation energies in such materials than the other frequently used generalized gradient approximation (GGA) potentials. Experimental CPs based on scaling of equal-valence-electron-density show a more covalent character of PbTiO3 than that of PbTi0.6Zr0.4O3 and PbZrO3, which is in consonance with the present LCAO based Mulliken's population charge reorganization data. The density of states, dielectric constants, frequency-dependent absorption spectra and refractive indices are computed using the modified Becke-Johnson potential as incarnated in the full-potential augmented plane wave method. The present optical response suggests the possibility of using PbTi1-xZrxO3 in the device for ultra-violet detection.