Full Potential Linearized Augmented Plane Wave Research Articles

Exploring ZnFeSnO4 double spinel: A thorough investigation of mechanical, dynamical, magneto-electronic properties and lattice thermal conductivity

Double spinel materials ABB'O4 emerge as an innovative class of oxides with promising technological applications. First-principles calculations are employed to explore the fundamental properties of the double spinel ZnFeSnO4. Its elasticity and dynamic stability are investigated using the pseudo-potential plane wave (PP-PW) method, while the full-potential linearized augmented plane wave (FP-LAPW) approach is used to study its electronic and magnetic properties. The results reveal favorable thermodynamic stability, mechanical robustness, and dynamical stability for ZnFeSnO4. Analysis using GGA + U (U = 6 eV) in the FP-LAPW framework predicts half-metallic ferromagnetism, a highly desirable characteristic for spintronic applications due to its potential spin-polarized currents. However, the use of the mBJ functional results in semiconducting character with bandgaps of 1.813 eV, and 1.524 eV for spin-up and spin-down, respectively. Hence, the outcomes of the computations pertaining to the electronic characteristics are contingent upon the selection of the exchange-correlation functional. Furthermore, the calculated low lattice thermal conductivity of ZnFeSnO4 indicates its potential suitability for thermoelectric applications.

Effect of Surface Functional Groups on the Electronic Behavior and Optical Spectra of Mn2N Based MXenes.

The extensive applications of MXenes, a novel type of layered materials known for their favorable characteristics, have sparked significant interest. This research focuses on investigating the influence of surface functionalization on the behavior of Mn2NTx (Tx=O2, F2) MXenes monolayers using the "Density functional theory (DFT) based full-potential linearized augmented-plane-wave (FP-LAPW)" method. We elucidate the differences in the physical properties of Mn2NTx through the influence of F and O surface functional groups. We found that O-termination results in half-metallic behavior, whereas the F-termination evolves metallic characteristics within these MXene systems. Similarly, surface termination has effectively influenced their optical absorption efficiency. For instance, Mn2NO2 and Mn2NF2 effectively absorb UV light ~50.15×104 cm-1 and 37.71×104 cm-1, respectively. Additionally, they demonstrated prominent refraction and reflection characteristics, which are comprehensively discussed in the present work. Our predictions offer valuable perspectives into the optical and electronic characteristics of Mn2NTx-based MXenes, presenting the promising potential for implementing them in diverse optoelectronic devices.

Analysis of structural, electronic and optical properties of Er-doped rock salt AlN using ab-initio calculations.

This investigation includes the structural and optoelectronic characteristics of both pure and Er-doped rock salt aluminium nitride (AlN). Upon introducing Er doping into the AlN host, the calculations reveal a rise in the atomic parameter. Incorporating Er into the system leads to enhancements in the static dielectric coefficient ɛ1(0), static reflectivity R(0), as well as static refractive index n(0), at zero frequency. After doping, the peaks of imaginary dielectric tensor, extinction coefficient and absorption coefficient shift towards lower energy levels. Various exchange correlation potentials are incorporated to compare the results of electronic and optical characteristics. We employed the full potential linearized augmented plane wave (FP-LAPW) approach with WIEN2k code in conjunction with the density functional theory (DFT). To explore the optoelectronic characteristics of both pure as well as doped systems, three distinct exchange correlation potentials are utilized: the Perdew-Burke-Ernzerhof Generalized Gradient Approximation (PBE-GGA), Modified Becke Johnson Generalized Gradient Approximations (mBJ + GGA) and Hubbard potential (GGA + U).

Insights into the DFT‐computed electronic and optical properties of binary and doped: Selenide for optoelectronic applications

AbstractThis study investigates the alterations in structural, electronic, and optical characteristics of ZnSe1−x Inx (x = 0%, 12.5%, 25%) employing the framework of density functional theory (DFT), utilizing generalized gradient approximation (GGA) in conjunction with the full‐potential linearized augmented plane wave (FP‐LAPW) approach. The findings reveal that pure ZnSe exhibits a direct bandgap of 1.79 eV at the Γ point, which reduces to 0 eV upon doping with Indium, indicating a transition to metallic characteristics. This change is attributed to the predominant involvement of the d‐orbital of Zn, s‐orbital of Se, and p‐orbitals of Indium in the valence band of ZnSe1−x Inx materials. Conversely, the s‐orbital of Zn predominantly contributes to the conduction band of undoped ZnSe, whereas the d‐orbitals of Indium play a significant role in the conduction band of ZnSe1−x Inx (x = 0%, 12.5%, 25%). Moreover, the study computes other optical parameters, including reflectivity, electron energy loss spectrum, extinction coefficient, refractive index, and absorption coefficient, as functions of photon energy. A notable observation is the considerable rise in the zero‐frequency dielectric constant, ε1(0), which increases from 5.0 in pure ZnSe to 40.0 and 50.0 in Indium‐doped ZnSe, highlighting a significant alteration in electronic properties. Furthermore, optical analyses demonstrate an expansion in the absorption coefficient spectrum, which extends from photon energies of 2.0 eV in pristine ZnSe to begin at 0 eV in Indium‐doped variants, indicating a broadening of the material's capacity to absorb light across a wider spectrum of photon energies. This expansion infers improved light absorption potential, which could be particularly beneficial for the fabrication of light‐emitting modules and solar energy converters. These insights underline the considerable influence that Indium incorporation exerts on the band architecture and optical responses of ZnSe, offering critical directions for the advancement of optoelectronic devices.

A comprehensive computational investigation on the physical properties of the chalcogenide ternary Y2ZnX4 (Y = In, Ga; X = S, Se) compounds

In this study, the structural, elastic, vibrational, electronic, optical, thermodynamic, and thermoelectric properties of the chalcogenide ternary Y2ZnX4 (Y = In, Ga; X = S, Se) compounds are comprehensively investigated using the pseudopotential plane-wave (PP-PW) and full-potential linearized augmented plane wave (FP-LAPW) methods. The analysis of elastic and vibrational properties reveals the dynamic and mechanical stability of these compounds. The calculated energy band gaps, ranging from 1.47 eV (Ga2ZnSe4) to 2.55 eV (In2ZnS4) in the visible spectrum, decrease as X atoms are substituted with S to Se. All examined compounds demonstrate favorable optical absorption (α > 105 cm-1) in the ultraviolet region. Notably, Ga2ZnSe4 exhibits absorption red-shift towards the visible region at hν = 2.76 eV due to its lower energy band gap, making it a promising candidate for solar cells. The three-dimensional representation of Young's modulus indicates significant deviation from sphericity, revealing anisotropic behavior in all compounds. Pugh's ratio, Poisson's ratio, and Cauchy's pressure analysis suggest ductile behavior in all four chalcogenide ternary compounds. Additionally, all compounds, except In2ZnS4, display auxetic properties. Finally, the calculated thermoelectric properties identify Ga2ZnS4 and In2ZnS4 as promising candidates for high-performance thermoelectric applications, with high Seebeck coefficients of 1848 and 1936 μV/K, respectively, and ZT values approaching unit.

Structural, band profiles and optical reflectivity studies of ALi2B (A = Cu, Ag; B = Ge, Sn, Pb) compounds

Abstract The subject of given project is to highlight the basic elastic, electronic and optical reflectivity of ALi2B (A = Cu, Ag; B = Ge, Sn, Pb). For the calculation of these properties, we used the full potential linearized augmented plane wave (FP-LAPW) procedures carry through Wien2k package. Specifically, the Perdew, Burke and Ernzerhof’s generalized gradient approximation (PBE-GGA) and Wu and Cohen generalized gradient approximation (WC-GGA) have been used. The obtained results fit well with existing experimental data. Different elastic parameters, such as constant of elasticity, elastic moduli, Poisson’s ratio, anisotropy factor and Cauchy pressure, are calculated for the first time for the compounds. The elastic properties clearly summarized the compound’s elastically stability and brittleness in both zinc blend phase. The band structure results for ALi2B shows that the compounds are metallic having overlapping bands across the electron chemical potential. The valance band highest energy state is composed from combination of Cu-d and Sn-p state, disclosed through these compound’s total (DOS) plots, whereas the conduction band primarily constitution is from Li-p, Sn-s Cu-s and Sn-p states. The intraband transitions play vital rule in the description of the optical reflectivity of the ALi2B compounds.

Exploring the Mn Doped BaTe Alloy for Spintronics and Energy Harvesting Applications

Abstract In the present study, the ferromagnetic semiconductor behavior of Mn doped BaTe is reported along with their physical properties. The calculations are done by full potential linearized augmented plane wave (FP-LAPW) approach within spin-polarized density functional theory (SP-DFT). Formation energies were computed to satisfy the stability of reported alloys. The spin-polarization is included in the calculations to study the electronic (band structure (BS), density of states (DOS)) and magnetic characteristics. Ba1-xMnxTe elucidates the magnetic semiconductor nature with direct band gap (Eg) in both spin channels while indirect Eg (1.66 eV) is observed for pure BaTe compound. Stable ferromagnetic (FM) states are vindicated owing to the p-d hybridization which are contributors in inducing magnetic moments (μB) at interstitial and non-magnetic sites. The optical parameters (reflectivity, absorption coefficient, refraction, optical conductivity and dielectric function) were computed within an energy range of 0-10 eV. Thermoelectric (TE) features are also figured using Boltaz-Trap code in terms of thermal and electrical conductivity, figure of merit, Seebeck coefficient and power factor. The analysis of optical parameters suggests that the considered alloys is active within visible to UV-range, having potential applications in optoelectronic, photovoltaic and thermoelectric applications.

Optoelectronic and mechanical properties of gallium arsenide alloys: Based on density functional theory

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.

Coupled Insights into Structural, Electronic, and Optical Properties of GeTMS3(TM=Sc, Fe, Zn) Sulfide Perovskite across Different Phases: Ab Initio Study

The structural stability analysis of various phases of GeTMS3(TM=Sc, Fe, Zn) sulfide perovskite has been conducted utilizing the WIEN2k package. This investigation leverages density functional theory (DFT) within the full potential linearized augmented plane wave (FP-LAPW) method, employing GGA-mBJ potentials. The focus of this study has encompassed the computation of structural, magnetic, and optical attributes across distinct GeTMS3 phases. These materials have been identified as promising contenders for applications in photovoltaics and spintronics. The study reveals the stability of various phases, with the orthorhombic phase proving energetically favorable for GeScS3 and GeZnS3, and the tetragonal phase for GeFeS3. Magnetic analyses indicate favorable ferromagnetic behavior in GeFeS3 and nonmagnetic characteristics in GeScS3 and GeZnS3. Furthermore, electronic examinations unveil semimetallic and semiconducting behaviors in GeScS3 and GeZnS3 in the tetragonal, respectively, with GeFeS3 exhibiting a half-metallic nature in the orthorhombic phase. Optical properties illustrate their potential as light harvesters, displaying characteristics suitable for energy conversion applications. This study contributes to a deeper understanding of sulfide perovskite properties, offering insights into potential applications in diverse technological fields.

First‐principles calculations to investigate structural, electronic, optical, and transport properties of half‐Heusler VFeZ (Z = N and P) compounds

AbstractThis research work investigates the structural, electronic, optical, and thermoelectric characteristics of VFeZ (Z = N and P) half‐Heusler compounds. The study employs the full‐potential linearized augmented plane wave (FP‐LAPW) method integrated into the WIEN2K algorithm, serving as the underpinning framework for density functional theory (DFT) analysis. In the study, we use the PBE generalized gradient approximation (PBE‐GGA) to identify numerous parameters associated with structural and elastic properties. Lattice parameter results are in agreement with previous outcomes. Moreover, computed elastic parameters satisfy the criterion for stability. In the cubic structure VFeZ (Z = N and P) is ductile, to enhance the computations of electronic characteristics, Tran and Blaha's modified Becke‐Johnson potential (TB‐mBJ) is used. Our simulations demonstrate that the materials exhibit semiconductor behavior, with a direct band gap for VFeZ (Z = N and P). Strong UV absorption is found via optical experiments suggest compounds are suitable for optical application. Furthermore, study of the thermoelectric properties suggests its application in the thermoelectric generators.

"Investigation of Structural, Electrical, Magnetic, and Optical Properties of Cu (111) and the Impact of Ag Adatoms Adsorption: A Density Functional Theory Study"

Our study conducts a comprehensive investigation on the structural, electrical, magnetic and optical properties of pure Cu with a (111) crystallographic orientation, as well as the impact of the adsorption of Ag adatoms on a Cu (111) surface. To perform this analysis, we utilized the full potential linearized augmented plane-wave (FP-LAPW) approach in conjunction with Generalized Gradient Approximations (GGA + U) and the Wien2k simulation software. Specifically, we calculated electrical and optical properties including the band structure, density of states (DOS) for the Cu (111) surface with and without the presence of adsorbed Ag atoms. Based on the observed results, the overlapping of the electronic bands for simple Cu (111) is comparatively less than that of adsorbed Ag/Cu (111) slab, indicating higher conductivity. Moreover, the evolutions are also observed which are mainly due to d orbitals of Cu and Ag for Cu (111) and Cu/Ag (111) respectively. The calculated magnetic optimization and weak diamagnetic magnetic moments shows weak diamagnetism in these materials. The optical properties like Dielectric Function(ε), Refractive index(n), Extinction co-efficient(k), Reflectivity(R), Energy Loss (L), Absorption (α) and Optical conduction (σ) are calculated. Our research examines the importance of band structure calculation in relation to optical properties. We discuss how plasmon-energy plays a crucial role in producing peaks in the energy loss function, with a crystallographic axis of 13.7eV and 13.6eV for both Cu (111) and Ag/Cu (111) slab. In addition, we calculated the static dielectric function, absorption coefficient, and refraction values for these materials. Reflectivity spectra for both Cu (111) and Ag/Cu (111) exhibits Infra-red region, indicating good coating materials to reduce heating, for the application of electrical appliances and for optical application like anti-reflecting coating, optical fibers and solar cells.

Computational investigation on the structural, electronic and optical characteristics of earth-abundant solar absorbers Cu2BeSnX4 (X= S, Se, Te)

This study aims to examine the equilibrium Kesterite structure of Cu2BeSnS4, Cu2BeSnSe4, and Cu2BeSnTe4 by the application of density functional theory (DFT) and the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method. The study demonstrates that both Cu2BeSnS4 and Cu2BeSnSe4 compounds are semiconductors with direct band gaps at the Γ point, while Cu2BeSnTe4 has an indirect band gap (Γ→X). The electronic and optical characteristics of these materials indicate their potential utility in optoelectronic, photonic, and photovoltaic applications. Furthermore, a thorough comparison has been conducted between the obtained results and other experimental and theoretical data from the same chalcogenide family. In summary, the findings offer valuable information on the possible photovoltaic uses of these compounds.

Investigation of AcXO3 (X = Al, Ga) perovskites for energy harvesting applications: a DFT approach

Full potential linearized augmented plane wave (FP-LAPW) based computational study is presented for AcAlO3 and AcGaO3. Tolerance factor (τG) is 0.93 for AcAlO3 and 0.90 for AcGaO3 which reveal the stability of proposed perovskite oxides in cubic phase. The calculated band structures for both materials reveal the nonmagnetic semiconductive nature with energy band gaps of 3.98 and 2.75 eV for respective Al and Ga based perovskites. Total, and partial density of states (DOS) are computed for meaningful understanding of semiconducting behavior of the proposed perovskites. The partially filled O-2p and Ac-6d states are observed to lie in the vicinity of Fermi level. Furthermore, various parameters of optical spectra have also been computed to study the light matter interaction. Moreover, thermoelectric (TE) properties of both materials have been investigated by using semiclassical Boltzmann theory with constant relaxation time approximation. Calculated figure of merit (ZT) values for AcAlO3 and AcGaO3 are 0.23 and 0.20 at 800 K, respectively. Overall, computational study for titled perovskites indicate that these materials have application in UV sensors, photovoltaic and thermoelectric devices.

Structural, electronic, magnetic, and optical properties of RE2ZrZnO6 (RE= La, Dy and Ho) double perovskites: experimental and DFT studies

In the present work, density functional theory (DFT) and experimental methods are used to examine the structural, electronic, optical, and magnetic characteristics of the RE2ZrZnO6 (RE = La, Dy, and Ho) double perovskites. The synthesis of these double perovskites oxides is done using the solid-state method. The orthorhombic structures are confirmed by XRD analysis. The EDS mapping shows the presence of La, Dy, Ho, Zr, Zn, and O with their required compositions, SEM images demonstrate the formation of well-shaped particles. On the theoretical side, Full potential linearized augmented plane wave (FP-LAPW) method is employed in the framework WIEN2k code. The half metallic nature of the studied compounds was revealed by spin polarized band structures and density of states. It was found that optical conductivity increases as photon energy increases up to a certain point, beyond the limit it begins to decrease. The comprehensive analysis reveals the studied compounds are potential materials for spintronic applications.

DFT and Monte Carlo simulations of Optical, Structural, electronic and Electrocaloric properties of Ca3Ti2O7 compound

Using the DFT we investigated the optical, structural and electronic properties of Ca3Ti2O7 with the full-potential linearized augmented plane-wave (FP-LAPW) approach with the code “Wien2k”. The lattice constants of Ca3Ti2O7 have been derived by the GGA-PBE approximation. We obtained an indirect energy band gap value of Eg = 1.774 eV between N and Γ points. The thermodynamic properties have also been calculated and debated. In addition, the absorption coefficient, reflectivity, optical conductivity, dielectric function, refractive index and extinction coefficient are achieved. In some cases, the electro-caloric properties of the Ca3Ti2O7 compound have been examined by Monte Carlo simulations. The polarization with different electric field values is also demonstrated. This polarization shows a phase transition from a ferroelectric to a para-electric state close to the Curie temperature TC equal to 1104.001 K. At last, the electric entropy changes of the temperatures have been inferred. To complete this study, we have calculated the relative cooling power (RCP) parameter for the corresponding Ca3Ti2O7 and the electrical hysteresis loops.

The impact of molybdenum and tungsten co-doping on the physical properties of CeO2: First-principles calculations

In this study, the WIEN2k code, utilizing the full potential linearized augmented plane wave (FPLAPW) approach within the framework of density functional theory (DFT), explicitly employing the PBEsol approximation, is employed to investigate the fundamental properties of W-doped and (Mo, W) co-doped cubic CeO2. Herein, lattice constants, bulk modulus and cell volumes were evaluated for structural properties. The total density of states (TDOS) for various doped and co-doped CeO2 systems was used to explain the origin of magnetic behavior. The band structure (BS) calculations show that the doped and co-doped materials exhibit semiconductor behavior with a direct bandgap in both spin channels. The calculated total spin magnetic moments of W/CeO2 and (Mo, W)/CeO2 alloys are 2.002[Formula: see text][Formula: see text] and 4.007[Formula: see text][Formula: see text] respectively. Furthermore, the optical absorption shows absorption peaks in the visible range and a redshift. As a result, adding molybdenum and tungsten additives improves the electro-optical properties of previous materials.

Theoretical investigation of structural, electronic, elastic, and optical properties of rubidium-based perovskites RbSrX3 (X = Cl, Br) for optoelectronic device applications – A DFT study

The search for environment-friendly lead-free halide perovskites is an emerging research area due to their crucial application in the field of photovoltaics and optoelectronics. So, in this current work, the structural, electronic, elastic, thermal, and optical properties of rubidium-based cubic halide perovskites RbSrX3 (X = Cl, Br) are investigated by the full potential linearized augmented plane wave (FP-LAPW) method in the context of density functional theory (DFT). The Generalized Gradient Approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) is implemented as the exchange-correlation potential. The structural stability of these compounds in the cubic phase is studied and the values of their formation energies and ionic filling fraction (IFF) have been assessed. The band structure and DOS plots reveal a wide indirect bandgap at zero pressure. The elastic constants of these compounds are evaluated, and from Blackman's and Every's diagrams, they are found to be elastically stable with a ductile and anisotropic nature. The optical parameters of these compounds imply that they show good response in the ultraviolet region. Thus, by experimentally synthesizing these compounds their potential application in the development of optoelectronic devices working in UV range can be assessed.

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.

Effect of SB Addition on Mechanical Electronic and Thermodynamic Properties of Intermetallic B2-NIAL: First Principles Study

Abstract This study investigates the mechanical, electronic, and thermodynamic properties of B2 NiAl alloyed with Sb, ranging from 0% to 100%. The calculations were conducted using the WIEN2k code based on the full potential linearized augmented plane wave (FP-LAPW) method within the density functional theory (DFT) framework. Generalized Gradient Approximation (GGA) was employed to approximate the exchange-correlation energy. Our analysis of formation enthalpy indicates a preference for Sb to substitute Al sites. Furthermore, we have observed that the mechanical properties of NiAl can be enhanced by adjusting the chemical composition of Sb. Specifically, an increase in antimony content from 0% to 75% results in a notable improvement in ductility tensile, elevating it from 1.92 to 10.72. Conversely, this alteration diminishes the material’s strength. Moreover, both the band structures and density of states (DOS) indicate the metallic behavior exhibited by all NiAl1-xSbx compounds. In addition, we employ the Gibbs2 code to calculate thermodynamic properties, shedding light on the influence of temperature and pressure on the volume, heat capacity, Debye temperature and entropy S of NiAl1-xSbx.

Comprehensive DFT investigation of X2MgSe4 (X = Dy, Tm) spinels for opto-spintronic and thermoelectric devices

Herein, a computational technique known as full potential linearized augmented plane wave (FP-LAPW) is applied for the analysis of magnetic, structural, optical, electronic, and thermoelectric features of X2MgSe4 (X= Dy, Tm) spinels within the density functional theory (DFT). Structural and thermodynamic stabilities are confirmed through the computation of tolerance factor (0.77) and formation enthalpies (-ve) for both spinels. Dy2MgSe4 behaves as a semiconductor with a 1.5 eV direct bandgap (Eg) in the majority spin state but as a metal in the minority spin state, resulting in its half-metallic ferromagnetic (HMF) nature. While Tm2MgSe4 demonstrated a semi-conducting nature in both spin up/down channels, with Eg of 1.41/1.34 eV, respectively. Absorption spectrum displays linear trend with peaks appearing at 6.10 eV for Dy2MgSe4 and 6.46 eV for Tm2MgSe4. Since peaks are appeared in the Ultraviolet (UV) region making them suitable materials for various optoelectronic application, including optical memory devices, sensors and optical filters. The calculated ZT values are 0.77 (at 800 K) and 0.766 (at 300 K), for Dy2MgSe4 and Tm2MgSe4, correspondingly. Overall, the study of X2MgSe4 (X = Dy, Tm) has shown a great potential for their potential usage in energy harvesting and spintronic applications.