O. V. Farberovich

Variation of the SbSI crystal energy gap at phase transition

Abstract Variation of the forbidden gap of SbSI crystals in the phase transition region is analyzed on the basis of calculations using the empirical pseudopotential method for the paraelectric (PEP) and ferroelectric phase (FEP). Other theoretical SbSI studies are critically reviewed. The band gap at several special points of the Brillouin zone and some characteristic parameters of the band structure are considered. At the ferroelectric phase transition, the variation of the direct and indirect gaps is mainly determined by variation of coupling between 3p-orbitals of S and 5p-orbitals of Sb. During the phase transition, the most significant changes are observed with the valence band top at points Q, C, R, H, E and with the conduction band bottom at points H, T and E of the Brillouin zone.

Electronic band structure of ferroelectric semiconductor SbSi studied by empirical pseudopotential

Abstract The choice of the empirical pseudopotential method for studying the electronic band structure of SbSI-type crystals is discussed. The method is applied to study the SbSI crystal in the paraelectric and ferroelectric phases. Differently from previous studies, a covalent crystal structure is assumed. The total density of states is calculated using the tetrahedron technique modified for treating orthorhombic crystals. The calculated total density of states is compared with the experimental X-ray spectroscopy data indicating good agreement between the theory and experiment. The composition of the bands is discussed. According to the calculations, in PEP the SbSI crystal shows indirect transition between points U and Z of the Brillouin zone, and in FEP it is between points R and Z. The minimum direct gap is for both phases at point U of the Brillouin zone.

Comparison of electronic structures of P and B impurities in nickel

Abstract The electronic structure of P and B impurities in Ni crystals has been calculated by the linear augmented plane wave (LAPW) Green-function method. The charge transfer is small and opposite in two alloys, and not very sensitive to structural changes in local order.

A “Giant Resonance” in Iron: Atom-Clusters-Crystal

Using the time-dependent local spin-density approximation and the model“atom in jellium” photoabsorpt ion cross-sections of iron clusters containing from 9 to 127 atoms have been calculated in the energy region of the giant resonance. The change of the shape of the giant resonance from a free Fe atom to iron clusters and bulk metal has been studied. It has been obtained that the intensity of the resonance is nonmonotonically decreased with the increase of iron atomic aggregation size.