Nonconventional screening of the Coulomb interaction in FexOy clusters: An ab-initio study

Abstract

From microscopic point-dipole model calculations of the screening of the Coulomb interaction in non-polar systems by polarizable atoms, it is known that screening strongly depends on dimensionality. For example, in one dimensional systems the short range interaction is screened, while the long range interaction is anti-screened. This anti-screening is also observed in some zero dimensional structures, i.e. molecular systems. By means of ab-initio calculations in conjunction with the random-phase approximation (RPA) within the FLAPW method we study screening of the Coulomb interaction in FexOy clusters. For completeness these results are compared with their bulk counterpart magnetite. It appears that the onsite Coulomb interaction is very well screened both in the clusters and bulk. On the other hand for the intersite Coulomb interaction the important observation is made that it is almost contant throughout the clusters, while for the bulk it is almost completely screened. More precisely and interestingly, in the clusters anti-screening is observed by means of ab-initio calculations.

References in corpus (9)

• Calculations of Hubbard U from first-principles
• Efficient implementation of the GW approximation within the all-electron FLAPW method
• Maximally Localized Wannier Functions within the FLAPW formalism
• Effective Onsite Interaction for Dynamical Mean-Field Theory
• Structure evolution of nanoparticulate Fe2O3
• Structure and magnetic properties of (Fe2O3)n clusters (n = 1-5)
• Magnetism and exchange interaction of small rare-earth clusters; Tb as a representative
• Geometric, electronic and magnetic structure of Fe${}_x$O${}_y^{+}$ clusters
• The valence and spectral properties of rare-earth clusters

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