Pnictides density

In the cellular multiple scattering model , finite clusters of atoms are subjected to condensed matter boundary conditions in such a manner that a continuous spectrum is allowed. They are therefore not molecular calculations. An X type of exchange was used to create a local potential and different potentials for up and down spin-states could be constructed. For uranium pnictides and chalcogenides compounds the clusters were of 8 atoms (4 metal, 4 non-metal). The local density of states was calculated directly from the imaginary part of the Green function. The major features of the results are ... 

This progression constitutes an approach towards a symmetrical octahedral environment for each pnictide atom (as in cubic black P), and is in accord with the increasing metallic character shown as the pnictides become heavier. This metallic character is indicated by the changing appearance and increasing values of density, coefficients of expansion, electrical and thermal conductivities which are observed on moving from phosphorus through to bismuth. 

Selected band results for the cerium pnictides. The angular momentum decomposition is a single-site decomposition of the wave function within the mufiln tins, not the LCAO decomposition. The radial charge density of the 4f-orbital at the muffine tin boundary and the valence band width (Ep - [,) are tabulated here as they enter into the discussion of relative peak heights (section 3.7). Units are atomic units except the band width which is given in electron... 

Although the effect of the spin-orbit interaction was included for the band peak, it was not for the supercell peak since the effect was thought to be too small to be worth the effort (the two f-electrons in the core used to construct the potential were treated as j = 5/2 states, though). Multiplet dfects were also not taken into account. In principle, this can be done in the local-density formalism (von Barth 1979), but has not been applied to solids to the authors knowledge. If multiplet effects turn out to be crucial for interpreting the BIS spectra of cerium pnictides, then an effort could be made to incorporate those effects into the calculation. 

The sum of the two contributions is a skew parabola with its minimum moved towards the beginning of the series. Further, the skewness and the distance of the minimum from the centre of the series increase as the strength of f-p hybridization increases, as shown in fig, 59. A model similar to that summarized in fig. 58 may also be used for actinide transition metal compounds, with d bands replacing the p bands of the chalcogenide or pnictide. The resulting state densities are then similar to those in fig. 40, modified to include f states in the bands, as in sect. 5.3 for cerium compounds. 

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