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The electronic, magnetic and optical properties of C- and N-doped CeO 2 bulk and (111) surface have been systematically investigated by first-principles calculations. The results show that the spin splitting occurs when doping atoms replace the anion sites in the CeO 2 matrix, causing a local magnetic moment of 2.00, and 1.00 μ B for C- and N-doping, respectively. The strong hybridization between dopants 2 p and O 2 p triplet-states around the Fermi level gives rise to the half-metallic character for doped bulk systems, while substitution onto the surface eliminates the degeneration of dopants 2 p orbitals, which results in anisotropic spin atmosphere. Especially, owing to the low formation energy and available RTFM, N-doped CeO 2 would be easily realized in the experiment and should also be wonderful candidate materials for oxide spintronics. In addition, compared with N-doped CeO 2 , the calculated optical properties reveal that C-doped CeO 2 (111) surface is able to enhance the absorption of the visible light. [ABSTRACT FROM AUTHOR]

Spin-polarized density functional theory (DFT) computations have been carried out to investigate Cr-, B-doping as well as codoping in the SrTiO 3 crystal. Impact of the oxygen vacancy as an intrinsic point defect has been also taken into consideration. In order to describe more precisely 3 d electrons of the Ti and Cr atoms, Hubbard-like U term in the DFT has been introduced. Outcomes of the calculations reveal occupied states within the forbidden energy region arguing that these in-gap states might be responsible for visible light photocatalysis in the SrTiO 3 . Structural and magnetic features of the doped and codoped material are discussed as well. [ABSTRACT FROM AUTHOR]

Structures and the physical properties of the current physical materials and other hypothetical models can be visualized and estimated with considerable success using density functional theory. As promising materials Double Perovskites satisfy the need of fulfillment of energy requirements in current scenario. Probing and investigating such structures theoretically, saves time and curtails the expenditure. This Perspective highlights the optical response functions viz Dielectric Tensor, Polarizability, Reflectivity, Optical conductivity, Absorption Coefficient and Extinction Coefficient of the material in the presence of electromagnetic field of varying energy (0–5eV) and offers an outlook of the potential use of such properties in spintronics and sensors. In our study the effective PBE (Perdew, Burke, Ernzerhof) functional was used to investigate the electronic and optical properties of Sr 2 FeMoO 6 and the thermodynamic stability of the material was estimated using the convex hull approach. The formation energy calculated from total energies of the bulk material (SFMO) and the individual total energies of the constituent elements in their corresponding pure bulk phase indicate the simulated structure to be thermodynamically stable with an energy value of −2.533eV. The study confirms SFMO as an anisotropic dispersive medium, with non-linear optical properties wherein apart from differential rates of absorption along different axis of polarization, nonlinearity and dispersion with respect to optical conductivity, dielectric constant can also be observed. The absorptive bandwidth of the material estimated by density functional approach lies between 2 and 4.5 eV and the absorption function resembles the Gaussian curve. The optical conductivity curve indicates that Sr2FeMoO6 is a direct band gap material with a bandgap of 2.1 eV. The absorption coefficient "μ" peaks at an energy values of 3.2 eV and the material is absorptive for most part of the ultra violet region. The pourbiax analysis of the material has been presented and the stability in presence of varying chemical potentials and pH scales suggest non toxicity and stability associated with the material. The extinction coefficient "K" for the two directions of polarizing field behave analogous to their respective imaginary dielectric functions and the peak value of the extinction coefficient shoots to 0.8. The reflectivity plots indicate the maximum reflectance reaches to about 0.2 (20% reflectance) and then decreases with the increase in the energy of the perturbing field. Spin Polarization and the observed TDOS (total density of sates) APDOS (atom projected density of states) graphics suggest that Sr 2 FeMoO 6 exhibits near-half metallic behaviour and can dramatically enhance device performance by controlling speed and various other properties wherein spin can be manipulated. Consequently, SFMO can be tailored for spintronic applications especially in case of multilayered spin-operated junctions/devices and nonvolatile memory elements, quantum computing and faster data processing speeds. • The theoretical predictions reported in this paper suggest that the material Sr2FeMoO6 is a semiconducting material with a bandgap of about 2.1eV. • Spin polarization, inclines the nonconducting behaviour of Sr 2 FeMoO 6 towards half metallicity. which can be harnessed for various spintronic applications like spin valves, memory elements, faster data processing etc. • The stability analysis suggests SFMO as a stable structure with a foramtion energy of -2.533eV.. • The pourbiax diagram analysis suggests presence of mixed/solid ion phases. [ABSTRACT FROM AUTHOR]

Recent progress in spin caloritronics has boosted exploration of materials for their application in this novel field. Heusler alloys which were being hailed as thermoelectric and magnetic materials have seen uprise for their suitable properties however lack of studies featuring good coupling between magnetic and thermoelectric properties have seen little impact in the field of spin-caloritronics. Present work explored doping of transition metal in a thermoelectric half-Heusler alloys NbCoSb on Nb site to induce spin-polarization and spin-dependent transport properties. Co (Mn) doping results in 98.09% (19.38%) negative spin polarization and 0.51 μ B /f.u. (1.98 μ B /f.u.) magnetic moment. Magnetic exchange parameter shows presence of long range RKKY-type interaction in Co and Mn doped NbCoSb. On one-hand, doping of Co and Mn in NbCoSb suppressed the electronic transport properties whereas, on the other hand spin dependent Seebeck effect is introduced. The synergistic effect of magnetic and thermoelectric properties in non-magnetic NbCoSb via doping of Mn and Co shows large variation in the value of Seebeck coefficient, electrical conductivity and electronic thermal conductivity with flipping of spin-directions suggests Co rich NbCoSb as a promising candidate for spin-caloritronics application. • Well known thermoelectric half-Heusler alloy NbCoSb is studied for spin-caloritronics. • Magnetism is induced in NbCoSb with Co and Mn doping. • High spin polarization and spin dependent Seebeck effect is introduced with Co doping. • Synergistic effect of thermoelectric and magnetic properties are reported. [ABSTRACT FROM AUTHOR]

A systematic and comparative theoretical study on the stabilization mechanism of titanium cluster has been performed by selecting the clusters Ti n ( n =3, 4, 5, 7, 13, 15 and 19) as representatives in the framework of density-functional theory. For small clusters Ti n ( n =3, 4 and 5), the binding energy gain due to spin polarization is substantially larger than that due to structural distortion. For medium clusters Ti 13 and Ti 15 , both have about the same contribution. For Ti n ( n =4, 5, 13 and 15), when the undistorted high symmetric structure with spin-polarization is changed into the lowest energy structure, the energy level spelling due to distortion fails to reverse the level order of occupied and unoccupied molecular orbital (MO) of two type spin states, the spin configuration remains unchanged. In spin restricted and undistorted high symmetric structure, d orbitals participate in the hybridization in MOs, usually by way of a less distorted manner, and weak bonds are formed. In contrast, d orbitals take part in the formation of MOs in the ground state structure, usually in a distorted manner, and strong covalent metallic bonds are formed. [ABSTRACT FROM AUTHOR]

The spin polarized electronic band structures, density of states (DOS) and magnetic properties of Mn 2 WSn, Fe 2 YSn (Y=Ti, V), Co 2 YSn (Y=Ti, Zr, Hf, V, Mn) and Ni 2 YSn (Y=Ti, Zr, Hf, V, Mn) huesler compounds are reported. The calculations are performed by using full-potential linearized augmented plane wave method (FP-LAPW) within density functional theory. The magnetic trend in these compounds is studied using values of magnetic moments, exchange interaction and calculated band gap. The results reveal that Mn 2 WSn and Ni 2 VSn show 100% spin polarization, Co 2 YSn (Y=Ti, Zr, Hf, Mn), Fe 2 YSn (Y=Ti, V), and Ni 2 MnSn exhibit metallic nature and Ni 2 YSn (Y=Ti, Zr, Hf) and Co 2 VSn show semi-conducting behavior. [ABSTRACT FROM AUTHOR]