Current Trends in Advanced Compound Materials

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Authors: Deepika Shrivastava, Sankar P. Sanyal
Abstract: The structural, electronic and elastic properties of CeTl with CsCl-type B2 structure have been investigated using full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT) within the generalized gradient approximation (GGA) for exchange and correlation potential. The ground state properties such as lattice constant, bulk modulus and pressure derivative of bulk modulus have been calculated which are in good agreement with available experimental data. The band structure and density of state depict that 4f electrons of Ce element have dominant character in electronic conduction and are responsible for metallic character of CeTl. The charge density plot reveals that the metallic as well as ionic bonding exist between Ce and Tl atoms. The calculated elastic constants indicate that CeTl is mechanically stable in cubic B2 phase and found to be ductile in nature.
Authors: Veena Thakur, Gitanjali Pagare, Sankar P. Sanyal
Abstract: A theoretical study of structural and electronic properties of NdPd3 intermetallic compound has been investigated systematically using first principles density functional theory. The calculations are carried out within LSDA for the exchange correlation potential. The ground state properties such as lattice parameter (a0), bulk modulus (B) and its pressure derivative (B′) are calculated and obtained lattice parameter of this compound shows well agreement with the experimental results. From energy dispersion curves, it is found that the studied compound is metallic in nature.
Authors: Namrata Yaduvanshi, Sadhna Singh
Abstract: In the present paper we have calculated the phase transition and volume collapse of Samarium Bismuthide under pressure using a three body interaction potential model which includes long range columbic interaction, three body interactions and short range overlap repulsive interaction operative up to second nearest neighbour. This compound undergoes transition from NaCl structure to body-centred tetragonal (BCT) structure (distorted CsCl-type P4/mmm). Our calculated results of phase transitions and volume collapses of SmBi are found to be close to the experimental results.
Authors: Nikita Acharya, Bushra Fatima, Sankar P. Sanyal
Abstract: The bonding nature as well as structural and electronic properties of cubic XPt3 (X=Sc and Y) intermetallic compounds, which crystallize in AuCu3-type structure have been investigated using a full-potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation (GGA). The equilibrium lattice parameters (a0), bulk modulus (B), pressure derivative of bulk modulus (B’) have been obtained using optimization method. Electronic properties of these compounds have been analyzed from band structure and Fermi surfaces.
Authors: Shubhangi Soni, Arvind Jain, Kamal Kumar Choudhary, Netram Kaurav
Abstract: A theoretical study of the elastic behavior in IrN compound using effective interionic interaction potential is carried out. The estimated values of phase transition pressure and the vast volume discontinuity in pressure-volume (PV) phase diagram indicate the structural phase transition from zinc blende (B3) to CsCl structure (B2). C11, C12 and C44 increase nearly linearly with pressure. At phase transition pressure IrN has shown a discontinuity in second order elastic constants, which is in accordance with the first-order character of the phase transition.
Authors: Chandrabhan Makode, Mahendra Aynyas, Jagdeesh Pataiya, Sankar P. Sanyal
Abstract: The density functional theory within generalized gradient approximation (GGA) has been used to calculate lattice parameter, total energy, phase transition pressure and electronic properties of neptunium sulphide (NpS). From our calculations we observe that NpS is stable in NaCl – type structure under ambient pressure. For this compound, the phase transition pressure was found to be 29.5 GPa. The nature of metallic behaviour is remarked from energy band diagram in NpS. All properties obtained for this compound are in good agreement with available results.
Authors: Sajad Ahmad Dar, Vipul Shrivastav, Umesh Kumar Sakalle
Abstract: Intermetallic compounds are innovative materials and are far superior to conventional metals and alloys. These intermetallic compounds have a great potential in industrial and technological fields because most of the intermetallic compounds are stronger as well asstiffer at elevated temperature and provide far better corrosion resistance than conventional metals and alloys.Over the past few years the scientific interest in the study of these intermetallic compounds emanates greatly because of their high-tech applications. Our motivation of the present studyMgTl mainly consernedon the physical data generation in context with its possible vast applications .We used a theoretical approach within the local density approximation method to study the structural and electronic properties of MgTl by calculating total energy. As far as our calculations are concerned, the band structure shows the overlapping of conduction and valence band thus itis clear that MgTl in its pure form is a good conductor of heat and electricity and falls in the category of metals. We have also calculated lattice parameters, bulkmodules, first order derivative electronic and lattice heat coefficient and Debye temperature.
Authors: Ekta Jain, Gitanjali Pagare, Sankar P. Sanyal
Abstract: An ab-initio investigation on structural, electronic, optical, elastic and thermal properties of CuZr intermetallic compound using full-potential linearized augmented plane wave method in the support of density functional theory at ambient condition have been performed. We have employed the generalized gradient approximation of (PBE) to indulgence the exchange correlation potential by solving Kohn-Sham equations. Total energy of CuZr as a function of the unit cell volume has been calculated using full potential linearized augmented plane wave (FP-LAPW) method in B1, B2 and B3 crystal structure to obtain the ground state properties. The study of different phases regarding their enthalpy vs. pressure variation is also presented. Our calculated structural parameters (a0 = 3.268 Å, B = 119 GPa and B' = 4.95) of CuZr are consistent with both the available experimental (a0 = 3.262 Å) and previously presented theoretical data (a0 = 3.280 Å, B = 121 GPa) for B2-type (CsCl) crystal structure. The results obtained from density of states (DOS) and optical spectra shows that the present compound is metallic. The value of density of states at the Fermi level N (EF) is found to 3.89 states/eV which is determined due to the contribution of ‘d’ like states of Cu and Zr and ‘p’ like states of Zr atom. The second order elastic constants are comparatively studied and an excellent agreement is found with other theoretical data. The trend of calculated elastic constants i.e. C11 - C12 > 0, C11 > 0, C44 > 0, C11 + 2C12 > 0 shows the stability criteria for B2-type (CsCl) crystal structure at ambient pressure. The sound velocities for longitudinal and shear waves, Debye average velocity and Debye temperature have been successfully calculated as a first theoretical prediction.
Authors: Shubha Dubey, Gitanjali Pagare, Ekta Jain, Sankar P. Sanyal
Abstract: The structural properties and electronic properties of the intermetallic compound ErPb3 which crystallize in AuCu3 type structure (AB3) 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 (a0), 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 (μm) of ErPb3 is 2.06.

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