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Highlights: [•] The available theoretical studies on the antiperovskites SbNCa3 and BiNCa3 were not consistent with the experiments. [•] These compounds are theoretically revisited with LDA, GGA, EV-GGA and mBJ potentials. [•] Both of them are found direct bandgap semiconductors. [•] The bandgaps for both of them is about 1.1eV. [•] Realizing the importance of these compounds in optical devices, optical properties are also discussed. [ABSTRACT FROM AUTHOR]

DFT studies are performed to investigate the structural, mechanical and magneto-electronic properties of the TlTF 3 (T=Fe, Co and Ni) perovskites for the first time using GGA, GGA+U and hybrid density functional theory (HF). Our calculations show that HF give better results than GGA and GGA+U and more consistent with the experiments. The comparison of the lattice constants calculated by HF with experiments shows a maximum underestimation less than 0.2%. The chemical bonding between different ions in these compounds is explained on the bases of electronic clouds, which reveals that in TlFeF 3 , Fe has more ionic character with F than the rest. The mechanical properties explain the hardness of these compounds and show that TlFeF 3 is more ductile. Spin-dependent electronic band profiles show that TlFeF 3 and TlCoF 3 are metallic, whereas TlNiF 3 is pseudo direct wide bandgap semiconductor. The stable magnetic phase optimizations and the calculated magnetic susceptibility confirm that TlFeF 3 and TlNiF 3 are ferromagnetic whereas TlCoF 3 is anti-ferromagnetic material. [ABSTRACT FROM AUTHOR]

Ferromagnetic metallic inverse-perovskite (Eu 3 O)In is studied using hybrid functional theory (HF) in the frame work DFT. The calculated structural parameters and geometries of the material are calculated by different exchange correlation potentials and found that HF results are closed to the experiments. Electronic charge density explains the bond nature and polarization. The spin polarized electronic band profiles and density of states reveal the metallic nature of the compound. The Eu f-state splitting show that the valance bands are dominated mainly by f-[a 2 ], f-[x(T 1 )], f-[y(T 1 )] and f-[z(T 1 )] states. The ground state magnetic phase of the compound is optimized. The optimum energy and magnetic susceptibility confirm the ferromagnetic nature of the compound. On the basis of different properties presented it is predicted that this compound is magnetoresistive material. [ABSTRACT FROM AUTHOR]

Abstract: Structural and electronic properties of the cubic perovskite ZnTiO3 and spinel Zn2TiO4 are theoretically studied by the modified Becke–Johnson (mBJ) potential within the framework of density functional theory (DFT). The calculated lattice constants are found to be consistent with the experimental results. The electronic band structures of both the materials reveal that ZnTiO3 is an indirect band gap while Zn2TiO4 is a direct band gap semiconductor. The calculated fundamental band gaps of these compounds are 2.7eV and 3.18eV, which are consistent with the experimental band gaps of 2.9eV and 3.1eV, respectively. Zn2TiO4 is a wide and direct band gap compound and hence is an attractive material for optoelectronic applications, especially in near ultraviolet (UV) optoelectronics. Keeping in view the importance of Zn2TiO4 in low frequency UV devices its optical properties like dielectric functions, refractive index, reflectivity and energy loss function are also evaluated and discussed in detail. [Copyright &y& Elsevier]

Osmium based perovskites AOsO 3 (A=Ca, Sr and Ba) have been studied theoretically using density functional theory approach. These studies show that CaOsO 3 and SrOsO 3 are orthorhombic and BaOsO 3 is cubic and are consistent with the experiments. The electronic band structures demonstrate that these compounds are metals. The magnetic studies verify the experimental observations at low temperature, where the spin effects are canceled by the orbitals. The stable magnetic phase optimizations and magnetic susceptibilities calculations by the post-DFT treatment confirm that CaOsO 3 and SrOsO 3 are weak ferromagnetic whereas BaOsO 3 is a paramagnetic material. The directional magnetic study shows that these compounds are magnetically anisotropic, and reveals that the easy magnetization axis is [001] direction. [ABSTRACT FROM AUTHOR]

The electronic properties of complex binary skutterudites, MX 3 (M = Co, Rh, Ir; X = P, As, Sb) are explored, using various density functional theory (DFT) based theoretical approaches including Green's Function (GW) as well as regular and non-regular Tran Blaha modified Becke Jhonson (TB-mBJ) methods. The wide range of calculated bandgap values for each compound of this skutterudites family confirm that they are theoretically as challenging as their experimental studies. The computationally expensive GW method, which is generally assume to be efficient in the reproduction of the experimental bandgaps, is also not very successful in the calculation of bandgaps. In this article, the issue of the theoretical bandgaps of these compounds is resolved by reproducing the accurate experimental bandgaps, using the recently developed non-regular TB-mBJ approach, based on DFT. The effectiveness of this technique is due to the fact that a large volume of the binary skutterudite crystal is empty and hence quite large proportion of electrons lie outside of the atomic spheres, where unlike LDA and GGA which are poor in the treatment of these electrons, this technique properly treats these electrons and hence reproduces the clear electronic picture of these compounds. [ABSTRACT FROM AUTHOR]

Mg-rich intermetallic NdNiMg 5 in orthorhombic phase with space group Cmcm (No. 63) has been studied theoretically using hybrid functional (HF–B3PW91) within the frame work of density functional theory (DFT). The calculated structural parameters and geometries are found in good agreement with the experiments. The electronic properties of the material reveal the metallic nature. Nd 4f-states splitting show that A 2 , y[t 1 ] and z[t 1 ] contributed in the valence band; x[t 1 ], ksi[t 2 ] and eta[t 2 ] in conduction band; where zeta[t 1 ] state completely lay at the Fermi level make the compound metallic. The electrical properties show that the material has significant conductivity above the room temperature. The stable magnetic phase of the compound is optimized which show that the material is stable in G-type antiferromagnetic (AFM) phase and Nd–Ni direct magnetic exchange interactions are involved. The calculated effective magnetic moments of Nd is 3.70 μ B per unit cell. The post-DFT calculations also confirm the AFM phase of the compound with Neel temperature (T N) = 25 K and Curie-Weiss constant (θ) = −23 K. Based on the above physical properties it is expected that this intermetallic could be used in spin valve and magnetic memory devices. • Mg-rich intermetallic NdNiMg 5 has been investigated theoretically using hybrid density functional theory. • The electronic properties of the material reveal the metallic nature. • The electrical properties show that the material has significant conductivity above the room temperature. • Stable magnetic phase of the compound is G-type anti-ferromagnetic phase. • The post-DFT calculations also confirm the AFM phase of the compound. [ABSTRACT FROM AUTHOR]