Band structure of new layered superconductors BaRh$_2$P$_2$ и BaIr$_2$P$_2$

The results of ab initio FLAPW-GGA computations of the band structure of two new layered low-temperature superconductors BaRh₂P₂ and BaIr₂P₂ (with a ThCr₂Si₂ tetragonal structure) are presented. As distinct from the family of the isostructural FeAs superconductors, they feature the complete replacement of the magnetic (Fe) metal by the nonmagnetic 4d (Rh) and 5d (Ir) metals. For BaRh₂P₂ and BaIr₂P₂, the energy bands, the distributions of the densities of electronic states, the Fermi surface topology, and the coefficients of the low-temperature electron specific heat and the molar Pauli paramagnetic susceptibility have been determined. An increase in T _C in the BaRh₂P₂ (1 K) → BaIr₂P₂ (2.1 K) transition can assumingly be attributed to the features of their phonon subsystem.