Electronic structure of metallic delafossite oxides

Metallic delafossites are materials which show intriguing properties revealed over the past years. This includes ultra-high conductivity, unconventional magnetism, and the potential to host strongly spin-orbit coupled states at their surfaces and interfaces. Structurally, they are layered materials with triangular in-plane lattices of transition metal atoms. This results in a quasi two-dimensional Fermi surface and very anisotropic transport properties.

a) Crystal structure of delafossite oxides. b) Fermi surface of PdRhO2 as measured in Arnold et al., Phys. Rev. B 96, 075163 (2017). The colors indicate the Fermi velocity. Images by Helge Rosner. — a) Crystal structure of delafossite oxides. b) Fermi surface of PdRhO₂as measured in Arnold *et al.*, Phys. Rev. B 96, 075163 (2017). The colors indicate the Fermi velocity. Images by Helge Rosner.

a) Crystal structure of delafossite oxides. b) Fermi surface of PdRhO₂as measured in Arnold *et al.*, Phys. Rev. B 96, 075163 (2017). The colors indicate the Fermi velocity. Images by Helge Rosner.

We study the Fermi surface topography of these compounds with our newly built state-of-the-art torque magnetometer in order to learn more about the electron interactions in the material and their influence on the transport properties. Quantum oscillation measurements give such a detailed knowledge of the Fermi surface and especially its c-axis warping parameters, that DFT calculations can be improved by a direct comparison. A comparison of the different compounds (PtCoO₂ and PdRhO₂) in the series allows to tune the spin orbit coupling and interactions terms.