High-pressure synthesis of Ba\(_2\)RhO\(_4\), a rhodate analogue of the layered perovskite Sr-ruthenate

• Published in: arXiv.org 2020-10
• Main Authors: Kurata, I, Flores-Livas, José A, Sugimoto, H, Takahashi, H, Sagayama, H, Yamasaki, Y, Nomoto, T, Arita, R, Ishiwata, S
• Format: Article
• Language: English
• Subjects: Barium; Crystal structure; Crystals; Electronic structure; Fermi surfaces; Perovskites; Software; Specific heat; Strontium; Superconductivity; Topology; X ray powder diffraction
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2010.06556

A new layered perovskite-type oxide Ba\(_2\)RhO\(_4\) was synthesized by a high-pressure technique with the support of convex-hull calculations. The crystal and electronic structure were studied by both experimental and computational tools. Structural refinements for powder x-ray diffraction data showed that Ba\(_2\)RhO\(_4\) crystallizes in a K\(_2\)NiF\(_4\)-type structure, isostructural to Sr\(_2\)RuO\(_4\) and Ba\(_2\)IrO\(_4\). Magnetic, resistivity, and specific heat measurements for polycrystalline samples of Ba\(_2\)RhO\(_4\) indicate that the system can be characterized as a correlated metal. Despite the close similarity to its Sr\(_2\)RuO\(_4\) counterpart in the electronic specific heat coefficient and the Wilson ratio, Ba\(_2\)RhO\(_4\) shows no signature of superconductivity down to 0.16 K. Whereas the Fermi surface topology has reminiscent pieces of Sr\(_2\)RuO\(_4\), an electron-like e\(_g\)-(\(d_{x^2-y^2}\)) band descends below the Fermi level, making of this compound unique also as a metallic counterpart of the spin-orbit-coupled Mott insulator Ba\(_2\)IrO\(_4\).