The development of new materials,having exceptional properties in comparison to existing materials is highly required for bringing advancement in electronic and optoelectronic technologies.Keeping this fact,we investi...The development of new materials,having exceptional properties in comparison to existing materials is highly required for bringing advancement in electronic and optoelectronic technologies.Keeping this fact,we investigated structural,electronic,and optical properties of zincblende GaN doped with selected Zn concentrations(6.25%,12.50%,and 18.70%),using the first-principle calculations based on density functional theory with GGA+U.We conducted the entire study using the WIEN2K code.In this study,we calculated various significant parametric quantities such as cohesive energies,formation energies,bulk moduli,and lattice constants along with the study of optical and electronic properties by substituting Ga atoms with Zn atoms in 1×2×2 supercell.The structural stability is confirmed by studying the phonon dispersion curves which suggest that Zn:GaN material is stable against the 6.25%and 18.70%Zn concentrations while for 12.50%,it shows instability.The Hubbard values U=0,2,4,6 eV were added to GGA and the electronic properties were improved with the U=6 eV.Optical absorption was blue shifted while the refractive index and dielectric constant were increased with increasing the Zn concentrations.Electronic properties are enhanced due to the prime contribution of cations(Zn)3ri states.The optical and electronic properties are further discussed in detail in the entire study.展开更多
Chemical bonding as well as structural,electronic and optical properties of CsPbF3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functio...Chemical bonding as well as structural,electronic and optical properties of CsPbF3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functional theory(DFT).The calculated lattice constant is found to be in good agreement with the experimental results.The electron density plots reveal strong ionic bonding in Cs-F and strong covalent bonding in Pb-F.The calculations show that the material is a direct and wide bandgap semiconductor with a fundamental gap at the R-symmetry point.Optical properties such as the real and imaginary parts of the dielectric function,refractive index,extinction coefficient,reflectivity,optical conductivity and absorption coefficient are also calculated.Based on the calculated wide and direct bandgap,as well as other optical properties of the compound,it is predicted that CsPbF_(3) is suitable for optoelectronic devices and anti-reflecting coatings.展开更多
In the present work,we investigate the structural,optoelectronic and thermoelectric properties of the YLi3X2(X = Sb,Bi) compounds using the full potential augmented plane wave plus local orbital(FP-APW+lo) method.The ...In the present work,we investigate the structural,optoelectronic and thermoelectric properties of the YLi3X2(X = Sb,Bi) compounds using the full potential augmented plane wave plus local orbital(FP-APW+lo) method.The exchangecorrelation potential is treated with the generalized gradient approximation/local density approximation(GGA/LDA) and with the modified Becke-Johnson potential(TB-mBJ) in order to improve the electronic band structure calculations.In addition,the estimated ground state properties such as the lattice constants,external parameters,and bulk moduli agree well with the available experimental data.Our band structure calculations with GGA and LDA predict that both compounds have semimetallic behaviors.However,the band structure calculations with the GGA/TB-mBJ approximation indicate that the ground state of the YLi3Sb2compound is semiconducting and has an estimated indirect band gap(Γ-L) of about 0.036 eV while the ground state of YLi3Bi2compound is semimetallic.Conversely the LDA/TB-mBJ calculations indicate that both compounds exhibit semiconducting characters and have an indirect band gap(Γ-L) of about 0.15 eV and 0.081 eV for YLi3Sb and YLi3Bi2respectively.Additionally,the optical properties reveal strong responses of the herein materials in the energy range between the IR and extreme UV regions.Thermoelectric properties such as thermal conductivity,electrical conductivity,Seebeck coefficient,and thermo power factors are also calculated.展开更多
By employing the spin resolved density functional theory, half-metallic character is investigated in Cs2NpBr6 having a K2PtCl6-type structure. The results precisely predict the half-metallic behavior of Cs2NpBr6. In s...By employing the spin resolved density functional theory, half-metallic character is investigated in Cs2NpBr6 having a K2PtCl6-type structure. The results precisely predict the half-metallic behavior of Cs2NpBr6. In spin-down state it presents an indirect band gap, while in spin-up channel it turns metallic. The structure optimization confirms the half-metallic nature in ferromagnetic configuration. The calculated magnetic moment is 3 μB toward which the main contributor is the Np atom.Furthermore, all the computed results are compared with the available experimental and theoretical values. According to the present analysis, we recommend Cs2NpBr6 for spintronic applications.展开更多
We investigate half metallicity in a chromium(Cr)-substituted AlN dilute magnetic semiconductor using the full-potential linearized augmented plane-wave method.Our results show that Al_(0.75)Cr_(0.25)N is half metal a...We investigate half metallicity in a chromium(Cr)-substituted AlN dilute magnetic semiconductor using the full-potential linearized augmented plane-wave method.Our results show that Al_(0.75)Cr_(0.25)N is half metal and holds a net integer magnetic moment of 3μβwith lattice compression.The half−metallic nature is maintained from the relaxed lattice constant 4.36Åto 4.09Å.An abrupt change of the physical properties is observed at a robust transition lattice constant of 4.09Å,and the material transforms from half metal to metal.We find that up to 6%compression,the material maintains its half-metallic nature.Furthermore,we also confirm that the origin of ferromagnetism in Al_(0.75)Cr_(0.25)N is double exchange.展开更多
Lead-free double perovskite halides are emerging optoelectronic materials that are alternatives to leadbased perovskite halides.Recently,single-crystalline double perovskite halides were synthesized,and their intrigui...Lead-free double perovskite halides are emerging optoelectronic materials that are alternatives to leadbased perovskite halides.Recently,single-crystalline double perovskite halides were synthesized,and their intriguing functional properties were demonstrated.Despite such pioneering works,lead-free double perovskite halides with better crystallinity are still in demand for applications to novel optoelectronic devices.Here,we realized highly crystalline Cs2AgBiBr6 single crystals with a well-defined atomic ordering on the microscopic scale.We avoided the formation of Ag vacancies and the subsequent secondary Cs3Bi2Br9 by manipulating the initial chemical environments in hydrothermal synthesis.The suppression of Ag vacancies allows us to reduce the trap density in the as-grown crystals and to enhance the carrier mobility further.Our design strategy is applicable for fabricating other lead-free halide materials with high crystallinity.展开更多
Anti-perovskites A3SnO(A=Ca,Sr,and Ba)are an important class of materials due to the emergence of Dirac cones and tiny mass gaps in their band structures originating from an intricate interplay of crystal symmetry,spi...Anti-perovskites A3SnO(A=Ca,Sr,and Ba)are an important class of materials due to the emergence of Dirac cones and tiny mass gaps in their band structures originating from an intricate interplay of crystal symmetry,spin–orbit coupling,and band overlap.This provides an exciting playground for modulating their electronic properties in the two-dimensional(2D)limit.Herein,we employ first-principles density functional theory(DFT)calculations by combining dispersion-corrected SCAN+rVV10 and mBJ functionals for a comprehensive side-by-side comparison of the structural,thermodynamic,dynamical,mechanical,electronic,and thermoelectric properties of bulk and monolayer(one unit cell thick)A3SnO anti-perovskites.Our results show that 2D monolayers derived from bulk A3SnO anti-perovskites are structurally and energetically stable.Moreover,Rashba-type splitting in the electronic structure of Ca3SnO and Sr3SnO monolayers is observed owing to strong spin–orbit coupling and inversion asymmetry.On the other hand,monolayer Ba3SnO exhibits Dirac cone at the high-symmetryΓpoint due to the domination of band overlap.Based on the predicted electronic transport properties,it is shown that inversion asymmetry plays an essential character such that the monolayers Ca3SnO and Sr3SnO outperform thermoelectric performance of their bulk counterparts.展开更多
文摘The development of new materials,having exceptional properties in comparison to existing materials is highly required for bringing advancement in electronic and optoelectronic technologies.Keeping this fact,we investigated structural,electronic,and optical properties of zincblende GaN doped with selected Zn concentrations(6.25%,12.50%,and 18.70%),using the first-principle calculations based on density functional theory with GGA+U.We conducted the entire study using the WIEN2K code.In this study,we calculated various significant parametric quantities such as cohesive energies,formation energies,bulk moduli,and lattice constants along with the study of optical and electronic properties by substituting Ga atoms with Zn atoms in 1×2×2 supercell.The structural stability is confirmed by studying the phonon dispersion curves which suggest that Zn:GaN material is stable against the 6.25%and 18.70%Zn concentrations while for 12.50%,it shows instability.The Hubbard values U=0,2,4,6 eV were added to GGA and the electronic properties were improved with the U=6 eV.Optical absorption was blue shifted while the refractive index and dielectric constant were increased with increasing the Zn concentrations.Electronic properties are enhanced due to the prime contribution of cations(Zn)3ri states.The optical and electronic properties are further discussed in detail in the entire study.
文摘Chemical bonding as well as structural,electronic and optical properties of CsPbF3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functional theory(DFT).The calculated lattice constant is found to be in good agreement with the experimental results.The electron density plots reveal strong ionic bonding in Cs-F and strong covalent bonding in Pb-F.The calculations show that the material is a direct and wide bandgap semiconductor with a fundamental gap at the R-symmetry point.Optical properties such as the real and imaginary parts of the dielectric function,refractive index,extinction coefficient,reflectivity,optical conductivity and absorption coefficient are also calculated.Based on the calculated wide and direct bandgap,as well as other optical properties of the compound,it is predicted that CsPbF_(3) is suitable for optoelectronic devices and anti-reflecting coatings.
基金the International Scientific Partnership Program ISPP at King Saud University for funding this research work through ISPP# 00
文摘In the present work,we investigate the structural,optoelectronic and thermoelectric properties of the YLi3X2(X = Sb,Bi) compounds using the full potential augmented plane wave plus local orbital(FP-APW+lo) method.The exchangecorrelation potential is treated with the generalized gradient approximation/local density approximation(GGA/LDA) and with the modified Becke-Johnson potential(TB-mBJ) in order to improve the electronic band structure calculations.In addition,the estimated ground state properties such as the lattice constants,external parameters,and bulk moduli agree well with the available experimental data.Our band structure calculations with GGA and LDA predict that both compounds have semimetallic behaviors.However,the band structure calculations with the GGA/TB-mBJ approximation indicate that the ground state of the YLi3Sb2compound is semiconducting and has an estimated indirect band gap(Γ-L) of about 0.036 eV while the ground state of YLi3Bi2compound is semimetallic.Conversely the LDA/TB-mBJ calculations indicate that both compounds exhibit semiconducting characters and have an indirect band gap(Γ-L) of about 0.15 eV and 0.081 eV for YLi3Sb and YLi3Bi2respectively.Additionally,the optical properties reveal strong responses of the herein materials in the energy range between the IR and extreme UV regions.Thermoelectric properties such as thermal conductivity,electrical conductivity,Seebeck coefficient,and thermo power factors are also calculated.
基金A.Laref was sponsored by the‘Research Center of Female Scientific and Medical Colleges’,Deanship of Scientific Research,King Saud University。
文摘By employing the spin resolved density functional theory, half-metallic character is investigated in Cs2NpBr6 having a K2PtCl6-type structure. The results precisely predict the half-metallic behavior of Cs2NpBr6. In spin-down state it presents an indirect band gap, while in spin-up channel it turns metallic. The structure optimization confirms the half-metallic nature in ferromagnetic configuration. The calculated magnetic moment is 3 μB toward which the main contributor is the Np atom.Furthermore, all the computed results are compared with the available experimental and theoretical values. According to the present analysis, we recommend Cs2NpBr6 for spintronic applications.
文摘We investigate half metallicity in a chromium(Cr)-substituted AlN dilute magnetic semiconductor using the full-potential linearized augmented plane-wave method.Our results show that Al_(0.75)Cr_(0.25)N is half metal and holds a net integer magnetic moment of 3μβwith lattice compression.The half−metallic nature is maintained from the relaxed lattice constant 4.36Åto 4.09Å.An abrupt change of the physical properties is observed at a robust transition lattice constant of 4.09Å,and the material transforms from half metal to metal.We find that up to 6%compression,the material maintains its half-metallic nature.Furthermore,we also confirm that the origin of ferromagnetism in Al_(0.75)Cr_(0.25)N is double exchange.
基金the National Research Foundation of Korea(NRF)grants funded by the Ministry of Science and ICT(NRF-2020R1F1A1057220)the Ministry of Education(NRF-2019R1A6A1A11053838)+4 种基金C.W.A acknowledges the support by Basic Science Research Program through the NRF funded the Ministry of Science and ICT(NRF-2018R1A2B6009210)Y.H.H.acknowledges the support by the NRF of Korea(NRF-2019R1I1A3A01063856)H.Y.J.acknowledges the support from Creative Materials Discovery Program(NRF-2016M3D1A1900035)Y.-H.S.acknowledges the support by Basic Science Research Programthrough the NRF funded the Ministry of Science and ICT(NRF-2018R1A2B6005159)Experiments at PLS-II were supported in part by MSICT and POSTECH.
文摘Lead-free double perovskite halides are emerging optoelectronic materials that are alternatives to leadbased perovskite halides.Recently,single-crystalline double perovskite halides were synthesized,and their intriguing functional properties were demonstrated.Despite such pioneering works,lead-free double perovskite halides with better crystallinity are still in demand for applications to novel optoelectronic devices.Here,we realized highly crystalline Cs2AgBiBr6 single crystals with a well-defined atomic ordering on the microscopic scale.We avoided the formation of Ag vacancies and the subsequent secondary Cs3Bi2Br9 by manipulating the initial chemical environments in hydrothermal synthesis.The suppression of Ag vacancies allows us to reduce the trap density in the as-grown crystals and to enhance the carrier mobility further.Our design strategy is applicable for fabricating other lead-free halide materials with high crystallinity.
基金The computations were enabled by resources provided by the Swedish National Infrastructure for Computing(SNIC)at HPC2N and NSC partially funded by the Swedish Research Council through grant agreement no.2018-05973.
文摘Anti-perovskites A3SnO(A=Ca,Sr,and Ba)are an important class of materials due to the emergence of Dirac cones and tiny mass gaps in their band structures originating from an intricate interplay of crystal symmetry,spin–orbit coupling,and band overlap.This provides an exciting playground for modulating their electronic properties in the two-dimensional(2D)limit.Herein,we employ first-principles density functional theory(DFT)calculations by combining dispersion-corrected SCAN+rVV10 and mBJ functionals for a comprehensive side-by-side comparison of the structural,thermodynamic,dynamical,mechanical,electronic,and thermoelectric properties of bulk and monolayer(one unit cell thick)A3SnO anti-perovskites.Our results show that 2D monolayers derived from bulk A3SnO anti-perovskites are structurally and energetically stable.Moreover,Rashba-type splitting in the electronic structure of Ca3SnO and Sr3SnO monolayers is observed owing to strong spin–orbit coupling and inversion asymmetry.On the other hand,monolayer Ba3SnO exhibits Dirac cone at the high-symmetryΓpoint due to the domination of band overlap.Based on the predicted electronic transport properties,it is shown that inversion asymmetry plays an essential character such that the monolayers Ca3SnO and Sr3SnO outperform thermoelectric performance of their bulk counterparts.
