Inst Mat Nantes Lab Chim Solides 2 Rue Houssimiere F-44072 Nantes 03 France
Univ Dusseldorf Inst Anorgan Chem & Strukturchem 2 D-40225 Dusseldorf Germany
Max Planck Inst Festkorperforsch D-70569 Stuttgart Germany

The electronic structures of ThCr₂Si₂-type compounds were studied by means of self-consistent LMTO band structure calculations. Different bonding interactions ini 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 band structures of superconducting LuNi₂B₂C 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 0.2eV higher in SrRh₂P₂. By doping, it should be possible to induce superconductivity in SrRh₂P₂ and related compounds.
© Copyright 1997 Academic Press.

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Journal of Solid State Chemistry, 130 254-265, 1997.