Osmates on the Verge of a Hund’s-Mott Transition: The Different Fates of NaOsO3 and LiOsO3

Daniel Springer, Bongjae Kim, Peitao Liu, Sergii Khmelevskyi, Severino Adler, Massimo Capone, Giorgio Sangiovanni, Cesare Franchini, and and Alessandro Toschi

We clarify the origin of the strikingly different spectroscopic properties of the chemically similar compounds NaOsO₃ and LiOsO₃. Our first-principle, many-body analysis demonstrates that the highly sensitive physics of these two materials is controlled by their proximity to an adjacent Hund’s-Mott insulating phase. Although 5d oxides are mildly correlated, we show that the cooperative action of intraorbital repulsion and Hund’s exchange becomes the dominant physical mechanism in these materials if their t_2g shell is half filled. Small material specific details hence result in an extremely sharp change of the electronic mobility, explaining the surprisingly different properties of the paramagnetic high-temperature phases of the two compounds.

Physical Review Letters, 125, 16, 166402, 2020-10-16.

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