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We report ab initio density functional theory calculations of the structural, elastic, electronic and optical properties of the double perovskite oxides Sr 2 AlXO 6 (X=Ta, Nb, V). We have predicted a direct Г–Г band gap in Sr 2 AlXO 6 (X=Ta, Nb) and an indirect Г–X band gap for Sr 2 AlVO 6 . The fundamental band gap increases linearly when the pressure is enhanced in the range 0–20 GPa. The frequency dependent of complex dielectric function, absorption, reflectivity and electron energy loss function were investigated in the range 0–40 eV. Features such as lattice constant, bulk modulus, elastic constants, band structure, total and local densities of states have been computed. [ABSTRACT FROM AUTHOR]

The PLANE WAVE pseudo-potential method within density functional theory (DFT) has been used to investigate the structural, elastic, electronic and optical properties of XCaF 3 (X = K and Rb) insulating. The studied compounds show a weak resistance to shear deformation compared to the resistance to the unidirectional compression. KCaF 3 and RbCaF 3 are considered ductile. The elastic constants and related parameters were predicted. The stiffness is more important in KCaF 3 , whereas, the lateral expansion is more important in RbCaF 3 . KCaF 3 and RbCaF 3 have R- Г indirect band gap. The main peaks in the imaginary part of the dielectric function correspond to the transition from the occupied state F − p to the unoccupied states Ca: s or K, Rb: p. At lower energies, KCaF 3 and RbCaF 3 show the same optical properties. Under pressure effect, the peaks of imaginary part of dielectric function were shifted toward high energy. [ABSTRACT FROM AUTHOR]

Abstract: The alkaline platinum hydrides are considered the most promising as hydrogen storage materials. The alloying ability of crystal, elastic constants and related parameters, electronic and optical properties have been studied using pseudo-potential plane–wave method based on the density functional theory. The investigated compounds show a weaker resistance to compression along the principal a-axis and their resistance to shear deformation is lower than the resistance to the unidirectional compression. The band structure indicates that A2PtH6 (A=K, Rb and Cs) are X–X direct gap semiconductors. The effective electron mass at equilibrium has been predicted towards X–Γ, X–W and L–W directions. The strong hybridization between Pt-d and H-s states in the upper valence band translates the existence of covalent bonding character in these compounds. The static optical dielectric constant is inverse proportional to the fundamental gap. [Copyright &y& Elsevier]

Abstract: Some physical properties of the cubic perovskites CsXF3 (X = Ca, Sr and Hg) have been investigated using pseudopotential plane-wave method based on the density functional theory. The calculated lattice parameters within GGA and LDA agree reasonably with the available experimental data. The elastic constants and their pressure derivatives are predicted using the static finite strain technique. We derived the bulk and shear moduli, Young''s modulus, Poisson''s ratio and Lamé’s constants for ideal polycrystalline aggregates. The analysis of B/G ratio indicates that CsXF3 (X = Ca, Sr and Hg) are ductile materials. The thermal effect on the volume, bulk modulus, heat capacity and Debye temperature was predicted. [Copyright &y& Elsevier]

Abstract: The structural, elastic, electronic and thermal properties of the MAX phases Ti 2 SiC and Cr 2 SiC are studied by means of the pseudo-potential plane wave method within GGA and LDA. The effect of pressure on the normalized lattice constants a/a 0 and c/c 0 and the internal parameter z is investigated. Our results of elastic constants, sound velocities and Debye temperature are predictions. The Ti 2 SiC and Cr 2 SiC compounds behave as ductile material and show a stronger anisotropy. The analysis of the band structure and density of states show that these compounds are electrical conductors, having a strong directional bonding between Ti and C and Cr and C atoms assured by the hybridization of Ti–d and Cr–d atom states with C–p atom states. The thermal effect on the primitive cell volume, bulk modulus, heat capacities CV and CP were predicted using the quasi-harmonic Debye model. [Copyright &y& Elsevier]

Abstract: A computed investigation on the structural, elastic, electronic, phonon frequencies and thermal properties of Al x Sc y B 1−x−y N quaternary alloys in the zinc-blend phase has been made with first-principles methods. The information on the lattice constant, lattice matching to AlN substrate and energy band gaps is indispensable for various practical applications. We have studied the effect of Sc concentration y (y =0, 0.152, 0.303, 0.455 and 0.607) on the lattice constant, bulk modulus, elastic constants C 11, C 12 and C 44, band gaps, optical phonon frequencies (ω TO and ω LO ), static and high-frequency dielectric coefficient ɛ(0) and ɛ(∞) and dynamic effective charge Z*. We remark an important deviation from the linear concentration dependence of the lattice constant and bulk modulus. The shear moduli, Young''s modulus, Poisson''s ratio were estimated in the frame work of the Voigt–Reuss–Hill approximation. The resistance to changes in bond length and lateral expansion in Al x Sc y B 1−x−y N increase with increasing y concentration. We observe that at y concentration about 0.11, the Г–X indirect fundamental gap becomes Г–Γ direct fundamental gap in Al x Sc y B 1−x−y N. There is well agreement between our results and the experiment data for AlN binary compound which is a support for those of the quaternary alloys that we report for the first time. [Copyright &y& Elsevier]

Abstract: Various physical properties of the cubic perovskite-type oxide BiScO3 have been investigated using the pseudo-potential plane-wave (PP-PW) method based on the density functional theory (DFT). The computed equilibrium lattice parameters agree well with the available theoretical data. The elastic constants and their pressure dependence are predicted using the static finite strain technique. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young’s modulus, Poisson’s ratio, average sound velocity and Debye temperature are numerically estimated in the framework of the Voigt–Reuss–Hill approximation for BiScO3 polycrystalline aggregate. The analysis of the site-projected -decomposed density of states, charge transfer and charge density shows that bonding is predominantly of ionic nature. We distinguish hybridization between Sc-d states and - states in the valence bonding region. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the thermal effect on the lattice constant, bulk modulus, heat capacities and thermal expansion coefficient is calculated. [Copyright &y& Elsevier]

Abstract: The structural, elastic, electronic, optical and thermal properties of the semiconductor perovskite CsPbCl3 were investigated using the pseudo-potential plane wave (PP-PW) scheme in the frame of generalized gradient approximation (GGA) and local density approximation (LDA). The computed lattice constant agrees reasonably with experimental and theoretical ones. The CsPbCl3 crystal behaves as ductile material. The valence bands are separated from the conduction bands by a direct band gap R–R. We distinguished hybridization between Pb-p states and Cl-p states in the valence bonding region. Under compression at P=30GPa, this material will have a metallic character. The thermal effect on the lattice constant, bulk modulus, Debye temperature and heat capacity C V was predicted using the quasi-harmonic Debye model. To the author''s knowledge, most of the studied properties are reported for the first time. [Copyright &y& Elsevier]

Abstract: Structural, elastic, electronic and thermal properties of the MAX phase Nb2SiC are studied by means of a pseudo-potential plane-wave method based on the density functional theory. The optimized zero pressure geometrical parameters are in good agreement with the available theoretical data. The effect of high pressure, up to 40 GPa, on the lattice constants shows that the contractions along the -axis were higher than those along the -axis. The elastic constants and elastic wave velocities are calculated for monocrystal Nb2SiC. Numerical estimations of the bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, average sound velocity and Debye temperature for ideal polycrystalline Nb2SiC aggregates are performed in the framework of the Voigt–Reuss–Hill approximation. The band structure shows that Nb2SiC is an electrical conductor. The analysis of the atomic site projected densities and the charge density distribution shows that the bonding is of covalent–ionic nature with the presence of metallic character. The density of states at Fermi level is dictated by the niobium d states; Si element has a little effect. Thermal effects on some macroscopic properties of Nb2SiC are predicted using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variations of the primitive cell volume, volume expansion coefficient, bulk modulus, heat capacity and Debye temperature with pressure and temperature in the ranges of 0–40 GPa and 0–2000 K are obtained successfully. [Copyright &y& Elsevier]

Abstract: The structural, elastic, electronic, optical and thermodynamic properties of the cubic perovskite-type hydride KMgH3 have been investigated using pseudo-potential plane-wave method based on the density functional theory. Computed equilibrium lattice constant agrees well with the available experimental and theoretical data. The elastic constants and their pressure dependence are predicted using the static finite strain technique. A linear pressure dependence of the elastic stiffnesses is found. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young’s modulus, Poisson’s ratio, average sound velocity and Debye temperature are numerically estimated in the frame work of the Voigt–Reuss–Hill approximation for KMgH3 polycrystalline aggregate. The analysis of the site-projected l-decomposed density of states and charge density shows that the bonding is predominantly of ionic nature. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the temperature effect on the lattice constant, bulk modulus, heat capacity and Debye temperature is calculated. [Copyright &y& Elsevier]

Abstract: The structural, electronic, optical and thermodynamic properties of Sr x Ca1−x O, Ba x Sr1−x O and Ba x Ca1−x O ternary alloys in NaCl phase were studied using pseudo-potential plane-wave method within the density functional theory. We modeled the alloys at some selected compositions with ordered structures described in terms of periodically repeated supercells. The dependence of the lattice parameters, band gaps, dielectric constants, refractive indices, Debye temperatures, mixing entropies and heat capacities on the composition x were analyzed for x =0, 0.25, 0.50, 0.75 and 1. The lattice constant for Sr x Ca1−x O and Ba x Sr1−x O exhibits a marginal deviation from the Vegard''s law, while the Ba x Ca1−x O lattice constant exhibits an appreciable upward bowing. A strong deviation of the bulk modulus from linear concentration dependence was observed for the three alloys. The microscopic origins of the gap bowing were detailed and explained. The composition dependence of the dielectric constant and refractive index was studied using different models. The thermodynamic stability of these alloys was investigated by calculating the phase diagram. The thermal effect on some macroscopic properties was investigated using the quasi-harmonic Debye model. There is a good agreement between our results and the available experimental data for the binary compounds which may be a support for the results of the ternary alloys reported here for the first time. [Copyright &y& Elsevier]

Abstract: The structural, elastic, electronic, optical and thermodynamic properties of the perovskite chloride CsCdCl3 were investigated using the pseudo-potential plane wave (PP-PW) within the Generalized Gradient Approximation (GGA) and Local Density Approximation (LDA). The computed lattice parameter agrees well with experimental and previous theoretical works. Based on the elastic constants and their related parameters, the crystal rigidity and mechanical stability have been discussed. Energy band structure shows that the investigated material is indirect energy band gap semiconductor. The static dielectric constant and static refractive index are indeed, proportional to the fundamental indirect band gap. The thermal effect on the lattice parameter, bulk modulus, volume expansion coefficient, Grüneisen parameter, heat capacities and Debye temperature were predicted using the quasi-harmonic Debye model. To the best of the authors’ knowledge, most of the studied properties are reported for the first time. [Copyright &y& Elsevier]

Abstract: Information on the energy band gaps, the lattice parameters and the lattice matching to available substrates is a prerequisite for many practical applications. A pseudopotential plane-wave method as implemented in the ABINIT code is used to the As x P y N1−x−y Al quaternary alloys lattice matched to AlP substrate to predict their energy band gaps and optical properties. The range of compositions for which the alloy is lattice-matched to AlP is determined. Very good agreement is obtained between the calculated values and the available experimental data. The Debye temperature increase when the bulk modulus is enhanced. We study the variation of elastic constants, the optical phonon frequencies (ω TO and ω LO ), the static and high-frequency dielectric coefficient ɛ(0) and ɛ(∞) and the dynamic effective charge Z * with P concentration (y). [Copyright &y& Elsevier]

Abstract: The structural, elastic, electronic and optical properties of XO (X= Ca, Sr and Ba) compounds were investigated by the density functional theory. A good agreement was found between our calculated results and the available theoretical and experimental data of the lattice constants. Young''s modulus, Poisson ratio, bulk modulus, elastic constants and their pressure derivatives are also calculated. SrO and BaO compounds present a transition phase at 39.72 and 27.28GPa. The SrO compound shows a change from direct band gap (Γ–Γ) to indirect band gap (Γ–X) at about 15GPa. The top of the valence bands reflects the s electronic character for all structures. We investigate the effective mass of electrons as function of pressure at the Γ point for CaO, SrO and BaO compounds. Calculations of the optical spectra have been performed for the energy range 0–60eV. The origin of the spectral peaks was interpreted based on the electronic structures. The enhancement of pressure increases the static dielectric function and refractive index of CaO, SrO and BaO. [Copyright &y& Elsevier]

Abstract: The stability, structural parameters, elastic constants, electronic and optical properties of perovskites CsCaH3 and RbCaH3 were investigated by the density functional theory. The calculated lattice parameters are in agreement with previous calculation and experimental data. The energy band structures, density of states, born-effective-charge and Mulliken charge population were obtained. The perovskites CsCaH3 and RbCaH3 present a direct band gap of 3.15eV and 3.27eV at equilibrium. The top of the valence bands reflects the s electronic character for both structures. Furthermore, the absorption spectrum, refractive index, extinction coefficient, reflectivity, energy-loss spectrum, and dielectric function were calculated. The origin of the spectral peaks was interpreted based on the electronic structures. The static dielectric constant and refractive index are indeed, inverse proportional to the direct band gap. [Copyright &y& Elsevier]

Abstract: Information on the energy band gaps, the lattice parameters and the lattice matching to available substrates is a prerequisite for many practical applications. A pseudopotential plane-wave method as implemented in the ABINIT code is used to the As x P y N1− x − y B quaternary alloys lattice matched to BP substrate to predict their energy band gaps and lattice dynamic properties. The range of compositions for which the alloy is lattice matched to BP is determined. Very good agreement is obtained between the calculated values and the available experimental data. The compositional dependence of direct and indirect band gaps has been investigated. We study the variation of elastic constants, the optical phonon frequencies (ω TO and ω LO), the high-frequency dielectric coefficient ε(∞) and the born effective charge Z ∗ with P concentration. [Copyright &y& Elsevier]

Abstract: We present structural, elastic, electronic and optical properties of the perovskites SrMO3 (M=Ti, and Sn) for different pressure. The computational method is based on the pseudo-potential plane wave method (PP-PW). The exchange-correlation energy is described in the generalized gradient approximation (GGA). The calculated equilibrium lattice parameters are in reasonable agreement with the available experimental data. This work shows that the perovskites SrTiO3, and SrSnO3 are mechanically stable and present an indirect band gaps at the Fermi level. Applied pressure does not change the shape of the total valence electronic charge density and most of the electronic charge density is shifted toward O atom. Furthermore, in order to understand the optical properties of SrMO3, the dielectric function, absorption coefficient, optical reflectivity, refractive index, extinction coefficient and electron energy-loss are calculated for radiation up to 80 eV. The enhancement of pressure decreases the dielectric function and refractive indices of SrTiO3 and SrSnO3. [Copyright &y& Elsevier]

We report the performance of glass/Mo/CuInSSe(CISSe)/(Zn 2 SnO 4 , CdS, SnS 2)/ZnO thin films structures using solar cell capacitance simulator (SCAPS). Thin films solar cells with CuInSSe absorber layer reduce the cost and have comparable performance parameters with the conventional ones. The temperature effect on efficiency and fill factor is less noticeable in solar cell with Zn 2 SnO 4 buffer layer. The average temperature gradient of CdS, SnS 2 and Zn 2 SnO 4 based cells value is -0.317 %/K, -0.533 %/K and -0.539 %/K. An efficiency of 18.53 % has been achieved with Zn 2 SnO 4 buffer for Voc, Jsc and FF of 0.5153 V, 45.4 mAcm−2 and 79.17. The desired thickness of the CuInSSe (CISSe) absorber layer is estimated as 1.8 μm. The best performance obtained with Zn 2 SnO 4 buffer can be explained by its higher transmission in the short wavelength range because its high gap 3.35 eV compared to those of CdS 2.4 eV and SnS 2 2.24 eV. [ABSTRACT FROM AUTHOR]

We studied the structural, elastic, electronic and optical properties of the orthorhombic NaMgH 3 , NaMgH 2 F, NaMgHF 2 and NaMgF 3 compounds. By means of the self-consistent CASTEP code, pseudopotentials, density functional theory in the LDA and GGA approximations, basic physical properties, such as lattice constant, shear modulus, elastic constants ( C ij ) and optical constants are computed. This study includes elastic parameters of mono and poly-crystalline aggregates. Derived elastic constants, such as bulk, Young's and Shear modulus, Poisson coefficient, Debye temperature and brittle/ductile behavior are estimated with the polycrystalline approach, using Voigt–Reuss–Hill theory. The calculations show that the orthorhombic Pnma structures are mechanically and dynamically stable in the pressure range (0–20 GPa). The calculated density of states shows that the orthorhombic compounds are insulators. [ABSTRACT FROM AUTHOR]

First-principle calculations using the Wien2k code and the GGA-mBJ exchange potential were used in the study of the thermodynamic, dynamic, chemical and elastic stability, as well as the electronic, optical and thermoelectric properties of Cs 2 (Sn, Pt, Te)I 6. The presence of an intermediate band in Cs 2 (Sn, Pt, Te)I 6 semiconductors confirmed by absorption peaks appeared at photon energy corresponding to the band gap enhances the efficiency of solar cells. The ideal band gap, high dielectric constants and optimal absorption make the double perovskites under study perform well in solar cells. The calculated minimum formation energy, Helmholtz free energy and phonon modes through the first Brillouin zone for the investigated Cs 2 (Sn, Pt, Te)I 6 family confirm their thermal, thermodynamic and dynamic stability. The acoustic phonon contribution modes come from the Cs-6s and I-5p electrons, while the Pt-6s, Sn-5p, Te-5p and I-5p electrons participate in the optical phonon modes. The narrowness of the upper valence band and the band gap in the visible region for C s 2 P t I 6 advantage this double perovskite in energy harvesting. The geometric Goldschmidt tolerance factor value between 0.8 and 1.0 and octahedral factor 0.41 indicate that C s 2 S n I 6 double perovskite is more stable. • We explore Cs 2 (Sn, Pt, Te)I 6 as potential thermoelectric materials because of their intrinsic p-type conductivity. • Efficient and high-performance thermoelectric materials such as Cs 2 (Sn, Pt, Te)I 6 exhibit low electronic thermal conductivity due to phonon-phonon scattering and optical emission. • The weaker elastic constants explain the large inter reticular distances and lower hardness and binding ionic forces. • The analysis of electronic structures proves that the band gap and optical gap in these materials are dictated by the energies of the empty (Sn-5s, Te-5p and Pt-6s) states at the lowest unoccupied band. • The efficiency of C s 2 S n I 6 , C s 2 T e I 6 and C s 2 P t I 6 in the conversion of heat into electrical energy is due to the p-type charge carriers, which give almost a factor of merite estimated at 83 %, 80.5 % and 78 %. • The considerable charge in the (Sn, Pt, Te)-I bonds due to a small difference in electronegativity and the hybridization between these levels reflects their covalent bonds. [ABSTRACT FROM AUTHOR]

Abstract: The structural, elastic, electronic and optical properties of the gallium monohydrides BaGaXH (X=Si, Ge, Sn) have been investigated by means of first principles calculations. The low values of the B/G ratio of these compounds correspond to the brittle nature, which is due to the hydrogen presence. The bulk modulus, Young's modulus, shear modulus decrease from Si to Sn for BaGaXH (X=Si, Ge, Sn) in the same column in the periodic table. Also the Debye temperature of these compounds has a relative high value indicating that they possess good thermal conductivity. The mean sound velocities have a progressive decrease from silicon (Si) to tin (Sn). [Copyright &y& Elsevier]

Abstract: We report a detailed study of the compositional dependence of the structural, elastic, electronic and dynamical properties of the quaternary alloys matched to AlP using pseudo-potential plane-wave method based on the density functional theory. The reliability and accuracy of the predicted physical properties mentioned above for are tested by comparing the calculated lattice constant, elastic constants and phonon dispersion curves for the binary AlP with the available experimental and theoretical data in the literature. [Copyright &y& Elsevier]

Abstract: A first-principles plane-wave pseudopotential method based on the density functional theory is used to investigate the structural, elastic and electronic properties of M4N5 and M5N6 (M = a transition metal (TM) Nb, Ta). C33 elastic constant for all compounds is found to be much larger than C11, indicating that a-axis is more compressible than c-axis. Interestingly, we find that C33 and C11 are significantly larger than other elastic constants, resulting in a pronounced elastic anisotropy. [Copyright &y& Elsevier]

Abstract: Using the plane-wave pseudopotential method, the total energy and electronic structure calculations of X y Ta1−y Ta2N3, (X=B, C, N, O, F) alloys have been performed to understand the structural stability and electronic properties. The exchange–correlation has been treated using the generalized gradient approximation (GGA). The virtual crystal approximation (VCA) was used to study the order/disorder to examine the effect of the substitution of B, N, C, O and F for Ta in the cell corner on the structural stability. The results show that the substitution of B, C, N, O and F for Ta at the corner sites slightly changes the lattice constant. We have evaluated the ground state quantities such as lattice constant, bulk modulus and elastic constants. We derived the bulk and shear moduli, Young’s modulus and Poisson’s ratio for an ideal polycrystalline c(X)(Ta2N3)(X=B,C,N,O,F) aggregate. Also, the results of densities of states are presented. The elastic, mechanical and electronic properties of c(X)(Ta2N3)(X=B,C,N,O,F) alloys are predicted. Also, the Debye temperature (), TDOS at the Fermi level , the X-p (X==B,C,N,O) states and the enthalpies of formation of the XTa2N3 compounds are investigated. [Copyright &y& Elsevier]

Abstract: The structural, elastic, electronic and optical properties of the cubic M3N4 (M = Zr, and Hf) have been studied for different pressure. The computational method is based on the Pseudo-Potential Plane-Wave method (PP-PW). The exchange correlation has been treated using the Generalized Gradient Approximation (GGA). We have evaluated the ground-state quantities such as lattice parameter, bulk modulus and its pressure derivative as well as the elastic constants. The elastic constants and their pressure dependence are calculated using the static finite strain technique. We derived the bulk and shear moduli, Young’s modulus and Poisson’s ratio for ideal polycrystalline Zr3N4 and Hf3N4 aggregate. Also, we have presented the results of the band structure and densities of states. Furthermore, in order to understand the optical properties, the dielectric function, optical reflectivity, refractive index, extinction coefficient, and absorption coefficient are calculated for radiation up to 20 eV. We predicted the elastic, electronic and optical properties of Zr3N4 and Hf3N4 compounds. [Copyright &y& Elsevier]

The Quaternary Heusler alloys CoFeXAs (X = Cr, Mn and V) fully spin-polarized with half-metallic stability, show low direct band gap, high absorption in the ultraviolet light, high spin polarization and adequate Seebeck coefficient. CoFeCrAs, CoFeMnAs and CoFeVAs have an integer magnetic moment of 4 μB, 5 μB and 3 μB according to the Slater-Pauling rule. The obtained minimal energy favors the type I CoFeVAs alloy over the type III CoFeCrAs and CoFeMnAs alloys. For CoFeCrAs and CoFeMnAs alloys, there is no band gap close to the Fermi level in the minority-spin, suggesting that they are direct Г–Г band gap semiconductors. Three-dimensional Co, Fe, and Mn atoms hybridized strongly, with little input from V and As atoms. Co, Fe, Cr, and Mn all have parallel magnetic moments, which results in ferromagnetic interactions between these atoms and gives these elements their ferromagnetic character. • The highest power factor affirms the general trend of thermoelectric efficiency of these studied materials. • Alloys under study with half-metallic stability, direct band gap in the minority-spin, high conductivity and absorption in the ultraviolet region, high spin polarization, adequate Seebeck coefficient are candidates for use in solar panels, spintronic and thermoelectric device applications. • CoFeXAs (X = Cr and Mn) alloys are fully spin-polarized and therefore called half-metallic. [ABSTRACT FROM AUTHOR]

All studied properties of FeX (X = Pt, Pd) in austenitic and martensitic phases are investigated within Local Spin Density Approximation as exchange functional. The structural parameters at equilibrium for ferromagnetic tetragonal FePt and FePd a = 3.911 Å, c = 3.842 Å and a = 3.816 Å, c = 3.736 Å, and the lattice constant for ferromagnetic cubic FePt and FePd a = 4.9304 Å and a = 4.905 Å agree well with their available theoretical and experimental data. FePd and FePt formation enthalpy of the martensitic phase was −12625.73 eV and −39414.97 eV, while in the austenitic phase it was −12625.33 eV and −39413.97 eV. The rock-salt FePd (tetragonal FePt) is more stable than tetragonal FePd (rock-salt FePt). For both compounds, the anisotropy is more pronounced in the martensitic phase. Fig. 4. Electron density for FePt (Fm "-"3 m) and FePt (P4/mmm) using LSDA. [Display omitted] • The band structure of FePt with spin-orbit coupling shows several bands crossing the Fermi level. • The Fermi level being occupied, all spin-polarized band structures exhibit metallic behavior for both the majority spin (spin up) and minority spin (spin down). • The ferromagnetism in FePt and FePd compounds comes from the coupling between Fe–Pt and Fe–Pd states. • The valence bands are formed as continuous board along the Г-X lines in the austenite phase of FePt and FePd in the spin up and spin dn cases. • Fe–Pt and Fe–Pd hybridization reduce the total magnetic moment, which is primarily obtained from Fe atoms with modest contributions from Pt and Pd sites. [ABSTRACT FROM AUTHOR]