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A study of the electronic and structural properties of germanium nanowires (GeNWs) was performed using the ab-initio Density Functional Theory within the generalized gradient approximation where electron-ion interactions are described by ultrasoft pseudopotentials. To study the effects of the lithium in the surface of the GeNWs we compare the electronic band structures of Hydrogen passivated GeNWs with those of partial and totally Li passivated GeNWs. The nanowires were constructed in the [001], [111] and [110] directions, using the supercell model to create different wire diameters. The results show that in the case of partial Li passivation there are localized orbitals near the valence band maximum, which would create a pdoped- kind of state. The total Li passivation created metallic states for all the wires. [ABSTRACT FROM AUTHOR]

The electronic transport as well as the effect of an external magnetic field has beeninvestigated on manganese-based materials, spinels and perovskites. Potential applications of double perovskites go from magnetic sensors to electrodes in solid-oxide fuel cells; besides thepractical interests, it is known that small changes in composition modify radically the physicalproperties of double perovskites. We have studied the Sr2FeMoO6 double perovskite compound(SFMO) using first-principles density functional theory. The calculations were done within thegeneralized gradient approximation (GGA) scheme with the Perdew-Burke-Ernzerhof (PBE)functional. We have made a detailed analysis of each electronic state and the charge densitymaps around the Fermi level. For the electronic properties of SFMO it was used a primitive cell, for which we found the characteristic half-metallic behavior density of states composed by egand t2g electrons from Fe and Mo atoms. Those peaks were tagged as bonding or antibondingaround the Fermi level at both, valence and conduction bands. [ABSTRACT FROM AUTHOR]