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Zusammenfassung:
The electronic structures of ThCr2Si2-type compounds mere studied by
means of self-consistent LMTO hand structure calculations. Different
bonding interactions in SrRh2P2 are analyzed and their dependence on the
electron count are discussed in terms of the formal substitution of
elements. The overall bonding situation can be characterized as an
interplay between covalent, metallic, and ionic interactions, although
metal-metal bonding plays an important role. Particularly, the evolution
of the interlayer bonding between the nonmetal atoms by changing the
transition metal is examined in more detail. It turns out that the
shortening of the interlayer bonds by filling the d shell of the
transition metal is due to an increasing occupation of nonmetal bonding
states which are pushed up to the vicinity of the Fermi level by
antibonding metal-nonmetal interactions. The hand structures of
superconducting EuNi2B2C and nonsuperconducting SrRh2P2 are compared and
their similarities are pointed out. A van Hove singularity, generated by
metal-metal interaction, coincides with the Fermi level in LuNi2B2C and
lies about 0.2 eV higher in SrRh2P2. By doping, it should be possible to
induce superconductivity in SrRh2P2 and related compounds. (C) 1997
Academic Press.