Using a tight-binding model and transfer-matrix technique, as well as Lanczos algorithm, we numerically investigate the nature of the ELECTRONIC states and electron transmission in site, bond and mixing Fibonacci model chains. We rely on the Landauer formalism as the basis for studying the conduction PROPERTIES of these systems. Calculating the Lyapunov exponent, we also study the localization PROPERTIES of ELECTRONIC eigenstates in the Fibonacci chains.. The focus is on the significance of the relationship between the transmission spectra and the nature of the ELECTRONIC states. Our results show that, in contrast to Anderson's localization theorem, in the Fibonacci chains the ELECTRONIC states are non-localized and the transparent states occurr near the Fermi level.

In the present work, the ELECTRONIC PROPERTIES of titanium were studied in three phases of a, b and w using the Density Function Theory (DFT). The full potential augmented plane wave plus local orbital (FLAPW+lo) method was applied using the generalized gradient approximation. The calculated total energies showed that omega phase was more stable than the two other phases. The largest electrical conductance was related to the b phase. These results were in good agreement with the findings of the previous works. In addition, these results showed that an increase in volume would lead to a decrease in energy; thus, causing an increase in the electrical conduction.

The ELECTRONIC and structural PROPERTIES of CaS are calculated using full potential linearized augmented plane wave (FPLAPW) method within the local density approximation (LDA) and generalized gradient approximation (GGA) for the exchange-correlation energy. For both structures, NaCl structure (BI) and CsCl structure (B2), the obtained values for lattice parameters, Bulk modulus and its pressure derivative and transition pressure are in reasonable agreement with the experimental values. For ELECTRONIC PROPERTIES, the obtained value for band gap is smaller than the experimental value as well as other calculated results based on density functional theory. Engel and Vosko calculated an exchange potential for some atoms within the so-called optimize-potential model and then used the virial relation and constructed a new exchange-correlation functional (EV-GGA). We used that functional and obtained reasonable results for band gap. Finally we investigated the possibility for a third phase (Zinc Blend structure) for this crystal.

Introduction of heteroatoms into C60 fullerene leads to enhance its physical and chemical PROPERTIES in one way or other. In this paper, we have studied C60 fullerene in which one of C6 hexagons is replaced by B3N3 using density functional theory at B3LYP/6-31G (d) level. The resulting heterofullerene B3N3C54 closely mimics the structure of C60 in which the polar BN bonds are weaker than covalent CC bond. The stabilization energy of B3N3C54 is found to be 5.35 eV. The vibrational infrared and Raman spectra of B3N3C54 have been calculated and compared with that of C60. The substitution results in a number of additions peaks including the strongest peak corresponding to BN stretching due to charge transfer from B to N atoms. The NMR chemical shifts of B3N3C54 have also been computed using GIAO approach. The ELECTRONIC parameters and DOS spectrum of B3N3C54 have been compared with C60 and their degenerate molecular orbitals have been plotted. The HOMO–LUMO energy gap of B3N3C54 is lowered by 0.1 eV as compared to C60.

We have studied the effect of impurity on ELECTRONIC PROPERTIES of single-walled carbon nanotubes using Density Functional Theory. ELECTRONIC band structures and density of states of (4, 4) and (7, 0) carbon nanotubes in the presence of different amount of B and N impurities were calculated. It was found that these impurities have significant effect on the conductivity of carbon nanotubes. The metallic (4, 4) nanotube remains to be metallic after doping with B and N. The ELECTRONIC PROPERTIES of small gap semiconducting (7, 0) tube can extensively change in the presence of impurity. Our results indicate that B-doped and N-doped (7, 0) carbon nanotubes can be p-type and n-type semiconductors, respectively.

In this study, the structural, ELECTRONIC, and optical PROPERTIES of InN in three phases of zinc, vortexite, and NaCl have been studied. The calculations have been performed using the pseudopotential method in the framework of Density Functional Theory (DFT) by Quantum espresso package with LDA, GGA, and PBE0 approximations for the exchange and correlation potential terms. The results show that the band gap for InN in the hexagonal phase is a semiconductor with a direct band gap while it is indirect in the NaCl phase. The mostly contributed in the valence band and in the conduction band of the s-orbital nitrogen atom and orbital s and p indium atoms. The result of the compressibility shows that the structural phase of the NaCl is less dense than the two structural phases. Also, the optical PROPERTIES of the compound including dielectric function, refractive index, electron energy loss Spectroscopy, and the results are consistent with other available data.

The ELECTRONIC structure and optical PROPERTIES in cubic cry stal BaTio3 are studied using-full-potential linearized augmented plane wave (FP-LAPW) method in density functional theory (DFT) with the generalized gradient approximation (GGA) by WIEN2K package. The calculated results of BaTio3 are in good agreement with other theoretical and experimental results.