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The electronic structure and density of states (DOS) of BaMnO3 compound are studied in the framework of density functional theory (DFT) using the generalized gradient approximation (GGA) and local density approximation (LDA). A number of different exchange-correlation functionals including hybrid (PBE, PZ and BLYP) exchange techniques have been used. The results show that in ambient conditions, the compound has metallic structure. It has been found from DOS calculations that the overlapping of bands near the Fermi energy are mainly due to the 3d state of Mn atoms. [ABSTRACT FROM AUTHOR]

The electronic structure, density of states (DOS), effective mass are calculated for tetragonal TlInSe2 from first principle in the framework of density functional theory (DFT). The electronic structure of TlInSe2 has been investigated by Quantum Wise within GGA. The calculated band structure by Hartwigsen-Goedecker-Hutter (HGH) pseudopotentials (psp) shows both the valence band maximum and conduction band minimum located at the T point of the Brillouin zone. Valence band maximum at the T point and the surrounding parts originate mainly from 6s states of univalent Tl ions. Bottom of the conduction band is due to the contribution of 6p-states of Tl and 5s-states of In atoms. Calculated DOS effective mass for holes and electrons are , , respectively. Electron effective masses are fairly isotropic, while the hole effective masses show strong anisotropy. The calculated electronic structure, density of states and DOS effective masses of TlInSe2 are in good agreement with existing theoretical and experimental results. [ABSTRACT FROM AUTHOR]

The electronic structure, density of states (DOS), effective mass are calculated for tetragonal TlInSe2 from first principle in the framework of density functional theory (DFT). The electronic structure of TlInSe2 has been investigated by Quantum Wise within GGA. The calculated band structure by Hartwigsen-Goedecker-Hutter (HGH) pseudopotentials (psp) shows both the valence band maximum and conduction band minimum located at the T point of the Brillouin zone. Valence band maximum at the T point and the surrounding parts originate mainly from 6s states of univalent Tl ions. Bottom of the conduction band is due to the contribution of 6p-states of Tl and 5s-states of In atoms. Calculated DOS effective mass for holes and electrons are , , respectively. Electron effective masses are fairly isotropic, while the hole effective masses show strong anisotropy. The calculated electronic structure, density of states and DOS effective masses of TlInSe2 are in good agreement with existing theoretical and experimental results. [ABSTRACT FROM AUTHOR]

Structural and magnetic properties as well as the electronic structures of Ru2YGe (Y = Cr,Mn) Heusler alloys were investigated in the framework of first principle calculation. Using the full-potential linearized augmented plane wave (FP-LAPW) in connection with the generalized gradient approximation (GGA) treatment of exchange-correlation energy, we have performed the structural optimization in the non-magnetic (NM) and three different magnetic configurations: FM, AFM-I and AFM-II. We have found that our two compounds are stable for the AFM-II state, which agree with the available experimental and theoretical results. The exchange constants J1 and J2 as well as the temperature of transition to the paramagnetic state (TN) were estimated here by the use of the energy difference method and the mean field approximation. The electronic structure of our compounds in their magnetic state was also studied. The GGA+U method has also been used to take into account the strong correlations among the d orbitals of Ru, Cr and Mn atoms. This has considerably improved both the electronic and magnetic results which became close to the corresponding experimental data. We have finally studied the thermodynamic properties using the quasi-harmonic Debye model as implemented in the Gibbs Program. [ABSTRACT FROM AUTHOR]

The full-potential linearized augmented plane wave method (FP-LAPW) within density functional theory, using the generalized gradient approximation, is used to study the structural and electronic properties of zinc-blende ByAlxGa1−x−yN quaternary alloys that match the lattice of an AlN substrate. The range of compositions, for which the lattice of the alloy matches AlN, is determined. Our calculated band structure, density of states, electron density and lattice parameter for ByAlxGa1−x−yN allow to accurately evaluate the profound effect that the incorporation of small amounts of Boron have on structural and electronic properties of AlxGa1−x−yN alloys. A comparison of the ground state properties with the available experimental and theoretical data is made for the compounds related to ByAlxGa1−x−yN and of the AlxGa1−xN alloys. The results show a strong dependence of the band gap (as well as the lattice parameter) on the Boron content, which might make ByAlxGa1−x−yN materials promising and useful for optoelectronic applications. [ABSTRACT FROM AUTHOR]