Authors: N.H. Hussin, Mohamad Fariz Mohamad Taib, Mohd Hazrie Samat, N. Jon, Oskar Hasdinor Hassan, Muhd Zu Azhan Yahya

Abstract: Ferroelectric materials of lanthanum (La) doped PbZrTiO_{3} (PLZT) were investigated via first principles study. The structural, electronic and optical properties of PLZT in tetragonal structure (P4*mm* space group) were performed in the framework of density functional theory (DFT) with generalized gradient approximation (GGA) and local density approximation (LDA) methods. The calculated results of structural properties of PLZT were seen to be approximately close to the experimental data. The results of the electronic part were covered with the calculation of energy band gap and density of states (DOS). The highest valence band (VB) which lies at the Fermi level (E_{F}) was dominated by the O 2p at F point. The conduction band (CB) of PLZT occurred at G point, which was primarily dominated by Ti 3d mixed at Pb and La p-state. Whereas the optical part was covered with the refractive index and absorption. The refractive index, *n* and the extinction coefficient, *k* were calculated with respect to photon energy. Those results obtained could be such a good prediction in studying parameters and properties of new materials.

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Authors: Shubha Dubey, Gitanjali Pagare, Ekta Jain, Sankar P. Sanyal

Abstract: The structural properties and electronic properties of the intermetallic compound ErPb_{3} which crystallize in AuCu_{3} type structure (AB_{3}) are studied by means of first principles total energy calculation using full potential linearized plane wave method (FP-LAPW) within the generalized gradient approximation of Perdew, Burke and Ernzrhof (PBE) and local spin density approximation (LSDA) for the exchange correlation functional and including spin magnetic calculation. The total energy is computed as a function of volume and fitted to the Birch-Murnaghan equation of state. The ground state properties of this compound such as equilibrium lattice parameter (a_{0}), bulk modulus (B), and its pressure derivative (B’) are calculated and compared with the available experimental results. We find good agreement with the other theoretical and experimental results. For the compounds, the values of lattice constants obtained by PBE-GGA overestimates and by LSDA underestimates the available experimental values for the same, which verifies the reliability of the present calculation. The value obtained for the bulk modulus is 50.63 GPa. The analysis of electronic properties is achieved by the calculation of the band structures and the density of states in both the spin up and spin down modes, which show a metallic character of ErPB3 due to zero band gap. The values of calculated density of states are found to be 0.36 eV/states and 11.46 eV/states in spin-up and spin-down mode respectively. The calculated magnetic moment (μ_{m}) of ErPb3 is 2.06.

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Authors: Gitanjali Pagare

Abstract: The ground state behavior of rare earth intermetallic compound TmPb_{3, }which crystallize in AuCu_{3} type structure, has been examined using first principles density functional theory based on full potential linearized augmented plane wave (FP-LAPW) method. Very few study on structural and electronic properties of TmPb_{3} compound has been available in the literature, which motivated us to perform the present study. The spin polarized calculations are carried out within the PBE-GGA and LSDA for the exchange correlation (XC) potential. Our calculated ground state properties such as lattice constant (a_{0}), bulk modulus (B) and its pressure derivative (B’) are in good agreement with the experimental results. The value of bulk modulus of TmPb_{3} is found to be 44.32 GPa and 55.01GPa by PBE-GGA and LSDA respectively. The electronic band structure (BS) and density of states (DOS) verify the metallic nature of this compound. The calculated density of states at the fermi level is found to be 0.16 states/eV and 19.50 states/eV for spin-up and spin-down modes respectively. The magnetic moment of TmPb_{3} is found to be 0.95.

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