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A theoretical study of the structural, elastic, electronic, mechanical, and thermal properties of the perovskite-type hydride CaNiH3 is presented. This study is carried out via first-principles full potential (FP) linearized augmented plane wave plus local orbital (LAPW+lo) method designed within the density functional theory (DFT). To treat the exchange–correlation energy/potential for the total energy calculations, the local density approximation (LDA) of Perdew–Wang (PW) and the generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof (PBE) are used. The three independent elastic constants (C11, C12, and C44) are calculated from the direct computation of the stresses generated by small strains. Besides, we report the variation of the elastic constants as a function of pressure as well. From the calculated elastic constants, the mechanical character of CaNiH3 is predicted. Pertaining to the thermal properties, the Debye temperature is estimated from the average sound velocity. To further comprehend this compound, the quasi-harmonic Debye model is used to analyze the thermal properties. From the calculations, we find that the obtained results of the lattice constant (a0), bulk modulus (B0), and its pressure derivative () are in good agreement with the available theoretical as well as experimental results. Similarly, the obtained electronic band structure demonstrates the metallic character of this perovskite-type hydride. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the structural, electronic and optical properties of InAs, InN and InP binary compounds and their related ternary and quaternary alloys by using the full potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). The total energies, the lattice parameters, and the bulk modulus and its first pressure derivative were calculated using different exchange correlation approximations. The local density approach (LDA) and Tran–Blaha modified Becke–Johnson (TB-mBJ) approximations were used to calculate the band structure. Nonlinear variations of the lattice parameters, the bulk modulus and the band gap with compositions x and y are found. Furthermore, the optical properties and the dielectric function, refractive index and loss energy were computed. Our results are in good agreement with the validated experimental and theoretical data found in the literature. [ABSTRACT FROM AUTHOR]

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 exchange–correlation 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 YLi3Sb2 compound is semiconducting and has an estimated indirect band gap (Γ–L) of about 0.036 eV while the ground state of YLi3Bi2 compound 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 YLi3Bi2 respectively. 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. [ABSTRACT FROM AUTHOR]

The structural, electronic, and magnetic properties of the Nd-doped Rare earth aluminate, La1−xNdxAlO3 (x = 0% to 100%) alloys are studied using the full potential linearized augmented plane wave (FP-LAPW) method within the density functional theory. The effects of the Nd substitution in LaAlO3 are studied using the supercell calculations. The computed electronic structure with the modified Becke–Johnson (mBJ) potential based approximation indicates that the La1−xNdxAlO3 alloys may possess half-metallic (HM) behaviors when doped with Nd of a finite density of states at the Fermi level (EF). The direct and indirect band gaps are studied each as a function of x which is the concentration of Nd-doped LaAlO3. The calculated magnetic moments in the La1−xNdxAlO3 alloys are found to arise mainly from the Nd-4f state. A probable half-metallic nature is suggested for each of these systems with supportive integral magnetic moments and highly spin-polarized electronic structures in these doped systems at EF. The observed decrease of the band gap with the increase in the concentration of Nd doping in LaAlO3 is a suitable technique for harnessing useful spintronic and magnetic devices. [ABSTRACT FROM AUTHOR]