Ab-initio calculations of the structural, electronic, magnetic, and optical properties of silicene substitutionally and interstitially doped with Zr, Nb, and Mo

<sec>Two-dimensional materials have shown excellent optical, mechanical, thermal or magnetic properties, and have promising applications in the high performance electronic, optical, spintronic devices and energy transfer, energy storage, etc. Monolayer transition metal silicide CrSi<sub>2</sub> has shown ferromagnetism and metal properties in previous studies, and it is expected to become a new two-dimensional material. The Ti, V, Co, Ni doped two-dimensional CrSi<sub>2</sub> are studied with different doping concentrations by using the first-principal pseudopotential plane wave method based on density functional theory, and electronic structure, magnetic and optical properties are calculated and analyzed. The results show that the density of states in the two-dimensional CrSi<sub>2</sub> system is asymmetric, and the crystal cells have obvious ferromagnetism with a magnetic moment of 3.55 <i>μ</i>B. Two-dimensional CrSi<sub>2</sub> has strong absorptivity and reflectivity in the far infrared and ultraviolet range, showing excellent optical properties.</sec><sec>The electronic structures and magnetic properties of Ti, V, Co or Ni doped CrSi<sub>2</sub> with different concentrations are calculated and analyzed, and the results show that the magnetic moment of the two-dimensional CrSi<sub>2</sub> varies after doping different elements at a doping concentration of 3.70 at%. After doping Ti, the magnetic moment of the system changes to 0 <i>μ</i>B at a doping concentration of 3.70 at%, showing that it is an indirect semiconductor. After doping V, the magnetic moment becomes smaller at a doping concentration of 3.70 at%, and the system has two degrees of freedom: electron charge and spin, showing the properties of diluted magnetic semiconductors. After doping Ni, the band gap <i>E</i><sub>g</sub>=0.09 eV appears in the spin-up band of the system at a doping concentration of 3.70 at%, while the spin-down band is metallic, and the system shows semi-metallic properties. The magnetic moment changes to 3.71 <i>μ</i>B after doping Ti at a doping concentration of 7.41 at%. After doping Co and Ni, the magnetic moment of the system becomes smaller at the doping concentration of 7.41 at%, and the spin-down 3<i>d</i> orbital electrons of ferromagnetic elements take the dominant position. After doping Ni, the magnetic moment becomes 0.37 <i>μ</i>B at the doping concentration of 7.41 at%. After doping Ti, the magnetic moment becomes 2.79 <i>μ</i>B at a doping concentration of 33.3 at at%, after doping V, the magnetic moment becomes 2.27 <i>μ</i>B, and the degree of spin becomes weaker at a doping concentration of 11.1 at%. After doping Co, the magnetic moment becomes 1.81 <i>μ</i>B at the doping concentration of 11.1 at%. The magnetic moment becomes 1.5 <i>μ</i>B after doping Ni at the doping concentration of 11.1 at%, which proves that the spin-up <i>d</i> orbital has less electronic contribution to the magnetic moment. The energy band range of each system is enlarged, and the interaction between atoms is enlarged, and the energy level splitting energy is enlarged at the doping concentration of 11.1 at%, which indicates that the effective mass of the system becomes smaller, the mobility of carriers turns stronger, and the metallization of materials grows stronger.</sec><sec>The optical properties of Ti, V, Co or Ni doped CrSi<sub>2</sub> with different concentrations are calculated and analyzed, and the results show that the two-dimensional CrSi<sub>2</sub> after being doped has good optical properties. For most of systems, their optical properties are improved and blue-shifted at the doping concentrations of 3.70 at% and 7.41 at%, but the absorption peak is red-shifted at the doping concentration of 11.1 at%. By studying the properties of doped two-dimensional CrSi<sub>2</sub>, it is found that the two-dimensional CrSi<sub>2</sub> has excellent electronic structure and optical properties, and the electronic structure, magnetic and optical properties of the two-dimensional CrSi<sub>2</sub> can be effectively changed by doping. Two-dimensional CrSi<sub>2</sub> is expected to be a promising material for preparing new high reliability and high stability spintronic devices, and the present research provides an effective theoretical basis for developing the two-dimensional CrSi<sub>2</sub> based devices.</sec>

The first-principles study of Ni-doped InN has been carried out to explore the doping effect of various charge states of Ni on the structural, electronic, magnetic, and optical properties of InN using generalized gradient approximation. Structural properties like lattice parameters, aspect ratios, bond lengths, and formation energies of (In, Ni) N are used to determine the stability of each doped system. The formation energies of (In, Ni)N systems decrease with the increase in charge state of nickel, while the bond lengths show an opposite trend. The DOS diagram shows that the introduction of Ni-d states within the bang gap region reduces the band gap for Ni(1+)- and Ni(2+)-doped InN, while the isolated states are generated in the case of Ni(3+)- and Ni(4+)-doped systems. The Ni(1+)-, Ni(3+)-, and Ni(4+)-doped InN systems are ferromagnetic in nature, whereas the (In, Ni(2+))N depicts spin-glass-like behavior. The best possible magnetization is obtained for (In, Ni(4+))N with a total magnet moment of 2.42 μB per supercell. Because of the presence of nickel impurities, the optical properties of InN have been significantly improved. The pure and Ni(3+)- and Ni(4+)-doped InN systems show nearly the same values of absorption edges (∼0.56 eV), in contrast with the Ni(1+)- and Ni(2+)-doped systems, where these values are 0.37 and 0.51 eV, respectively. The shift in absorption edges of Ni(1+)- and Ni(2+)-doped InN to lower energies and increase in the intensity of absorption and broadening of absorption peaks can be attributed to the pronounced band-gap reduction for these systems. A negligible shift of absorption edges in the case of Ni(3+)- and Ni(4+)- doped InN is the characteristic of isolated charge states introduced around the Fermi level, which inhibit the band gap reduction, and hence the optical properties are not improved as expected. This study demonstrates an important fact that for best possible optical device applications Ni(1+)-doped InN system is excellent, while for better magnetic properties the (In, Ni(4+))N is more suitable.

The work presented in this manuscript is a study of structural, magnetic, and optoelectronic properties of CuMnSe2-chalcopyrite by FP-(L)APW + lo method using semilocal and hybrid functional. Structural properties such as cell parameters, bulk modulus, and its pressure derivative, as well as the cohesive energy and total energy of the unit cell were determined for the three magnetic phases (AFM, FM, and NM) from which it has been found that CuMnSe2-chalcopyrite is ferromagnetic. The studied elastic properties confirm the mechanical stability of CuMnSe2 in its chalcopyrite structure. Electronic properties, such as the band gap energy, density of states, and charge density, and magnetic properties, such as Hubbard term estimation, magnetic moment, and polarization of the CuMnSe2, have been predicted by several methods (GGA-PBEsol + U eff, GGA-PBEsol_(mBJ) + U eff, and hybrid functional). Optical properties such as the analysis of the dielectric function and the prediction of the refractive index and birefringence variations were also studied.

The structural, elastic, electronic, magnetic and optical properties of SrNiO3 perovskite: A DFT and DFT+U study

Ab initio calculations are performed to investigate theoretically the structural stability, electronic, magnetic, and elastic properties of dilute magnetic semiconductors Ca0.75TM0.25S (TM = Mn, Co, and Ni). These materials crystallize in the ferromagnetic rock-salt phase and are made by doping the CaS binary semiconductor with transition metals at a fixed concentration. Calculations are performed using the full-potential linearized augmented plane wave method, plus the local orbital method (FP-LAPW+lo). The correlation exchanges potential and the structural properties are calculated using the generalized gradient approximation proposed by Perdew-Burk-Ernzerhof (PBE-GGA) and the electronic and magnetic properties are calculated using the Becke and Johnson modified local density approximation (mBJ–LDA). The comparison of curves giving energy as a function of volume in the fundamental state of the compounds in the ferromagnetic (FM), antiferromagnetic (AFM), and paramagnetic (PM) phases presented that the compounds are stable in the ferromagnetic phase. Analysis of the electronic properties showed that Ca0.75Mn0.25S, Ca0.75Co0.25S, and Ca0.75Ni0.25S are all ferromagnetic semiconductors. Various parameters like spin-exchange splittingΔx(d), crystal field energyΔECrystal, and exchange constants N0αand N0β have also confirmed a stable ferromagnetic state. The magnetic study revealed a strong contribution to the value of the total magnetic moment of the compounds, with low contributions coming from the non-magnetic atoms Ca and S. The Curie temperature values, calculated by the mean-field approximation, are 240.78 K, 228.79 K, and 150.31 K in the compounds containing Mn, Co, and Ni, respectively. The study of the mechanical properties of the host semiconductors CaS doped with transition metals, Mn, Co, and Ni, carried out at zero pressure has shown that all compounds are brittle and mechanically stable.

Context and Methods Palladium-based vacancy-ordered perovskites A₂PdCl₆ (A = K, Rb, Cs) exhibit promising structural, electronic, magnetic, and thermoelectric properties. They crystallize in an Fm3̅m symmetry, with electronic transitions dominated by Pd d- and Cl p-orbitals. Their thermoelectric efficiency depends on electrical conductivity, Seebeck coefficients, and thermal conductivity. Density functional theory (DFT) calculations were performed using WIEN2k with the PBE functional, incorporating spin-orbit coupling where necessary. Electronic properties were analyzed via density of states (DOS) and band structure calculations. Thermoelectric properties were evaluated using Boltzmann transport theory via BoltzTraP. The figure of merit (ZT) was computed to assess thermoelectric efficiency. Magnetic properties were studied through spin-orbit coupling effects. These insights highlight the potential of A₂PdCl₆ for sustainable energy and electronic applications.

Electronic structure and magnetic properties of the [formula omitted] compound

We report on how Co substitution of the Fe sites of pseudobrookite (Fe2TiO5) influences the crystal structure, high-temperature electric permittivity, impedance, electronic structure, magnetic, and optical properties via experimental and theoretical investigations. The pseudobrookite phase contains two types of octahedral sites, Fe atoms reside on type of the sites while Ti on the others and replacing Fe with Co can have a huge influence on one or more physical properties that can render the material more useful for solar energy applications. X-ray diffraction and high-temperature electric permittivity/impedance were the experimental tools used. A temperature range of 20-300 °C and a frequency range of 100 Hz to 1 MHz were used for studying various types of relaxation mechanism via impedance analysis, including grains, grain boundaries, and interfacial effects. To explore the electronic structure, magnetic, and optical properties from first principles, dispersion-corrected density functional theory (PBE-D2/U) was employed. The structure as well as the electric impedance properties are impacted slightly by the Co substitution of Fe in Fe2TiO5 whereas the electronic structure and magnetic properties are influenced significantly. The bandgap is reduced slightly and the average magnetic moment per Fe ion is reduced upon Co substitution of Fe in Fe2TiO5.

Structural, electronic and magnetic properties of three semi-Heusler compounds of CoTiSb, NiTiSb and FeTiSb were calculated by the method (FP-LAPW) which is based on the DFT code WIEN2k. We used the generalized gradient approximation (GGA (06)) for the term of the potential exchange and correlation (XC) to calculate structural properties, electronic properties and magnetic properties. Structural properties obtained as the lattice parameter are in good agreement with the experimental results available for the electronic and magnetic properties was that: CoTiSb is a semiconductor NiTiSb is a metal and FeTiSb is a half-metal ferromagnetic.

Three newly designed pyrochlore oxides, Eu2Tm2O7 (Tm = Hf, Sn, Zr), are analyzed for their magnetic, optical and electronic properties using ab-initio calculations within the context of density functional theory (DFT). We can refer these compounds as direct bandgap materials because there is a very slight difference between the height of bands at the Γ- and M-point. It is observed that bandgap engineering can be performed by replacing Hf with Sn and Zr. It is observed from total density of states (TDOS) plots that shape and height of curves is not the same in spin up and spin down channels, showing significant magnetic moment in these compounds. It is evident from magnetic properties that a major portion of total magnetic moment (mtot) comes from Eu-atoms. In all compounds, the magnetic moment of O, Hf, Sn and Zr atoms is negative, whereas the magnetic moment of Eu-atoms is positive, showing their antiparallel arrangement. In both spin channels, significant absorption of the incoming photons is also shown by these compounds in the ultraviolet (UV) region. We can conclude on the basis of Rω that these compounds can be utilized in applications such as anti-reflecting coatings. These compounds are potential candidates for photovoltaic applications, such as solar cells, due to efficient absorption of incoming photons in visible and UV regions.

A comparative study of electronic structure and magnetic properties of SrCrO3 and SrMoO3

A review on DFT + U scheme for structural, electronic, optical and magnetic properties of copper doped ZnO wurtzite structure

Structural, mechanical, thermal, electronic and magnetic properties as well as the energy of formation and the Curie temperature of PrXO3(X = Al, Ga) are investigated by using first- principles calculations based on density functional theory (DFT). The exchange-correlation potential was treated with the generalized gradient approximation (GGA) for the structural properties. Moreover, the GGA + U approximation (where U denotes the Hubbard Coulomb energy U term) is employed for the magnetic and electronic properties. We have also used some analytical techniques to compute different structural and elastic parameters. The calculated lattice constants are in good agreement with the available experimental and theoretical results. The elastic constant and their derived moduli reveal that PrAlO3 is brittle and PrGaO3 is ductile in nature. The band structure and the density of states calculations with GGA and GGA + U predicted a metallic nature for PrGaO3 and a half metallic behavior for PrAlO3. The grounds states energies indicate that PrGaO3 is stable in paramagnetic phase while PrAlO3 in ferromagnetic phase.

Electronic, magnetic, optical and elastic properties of Fe2YAl (Y=Ti, V and Cr) using first principles methods

Abstract: The structural, electronic and optical properties of Al0.50Ga0.38In0.12N0.03Sb0.97 have been investigated using a full potential linearized augmented plane wave (FP-LAPW) method within the local density approximation (LDA).The structural properties such as the lattice parameter, bulk modulus B, pressure derivative B’ are determined and electronic properties such as band gap and density of states have been pursued. On the other hand, the dielectric function, refraction index, reflectivity, conductivity function, and energy-loss spectra were obtained and analyzed on the basis of electronic band structures and density of states.