This is an exciting work we have the opportunity to collaborate with experimental colleagues at the University of Osaka.
A new layered perovskite-type oxide Ba2RhO4 was synthesized by a high-pressure technique and predicted by our calculations. The crystal and electronic structure were studied by both experimental and computational tools. Structural refinements for powder x-ray diffraction data showed that Ba2RhO4 crystallizes in a K2NiF4-type structure, isostructural to Sr2RuO4 and Ba2IrO4. And we perform magnetic, resistivity, and specific-heat measurements for polycrystalline samples of Ba2RhO4, which indicated that the system can be characterized as a correlated metal. Despite the close similarity to its Sr2RuO4 counterpart in the electronic specific-heat coefficient and the Wilson ratio, Ba2RhO4 shows no signature of superconductivity down to 0.16 K. In contrast, the Fermi surface topology has reminiscent pieces of Sr2RuO4, an electronlike eg-(dx2−y2) band descends below the Fermi level, making this compound unique also as a metallic counterpart of the spin-orbit coupled Mott insulator Ba2IrO4.
This work is now published in Phys. Rev. Materials (January 2021)