Spin-orbit coupling, strong correlation, and insulator-metal transitions: The J(eff)=3/2 ferromagnetic Dirac-Mott insulator Ba2NaOsO6

Article

关键词: MAGNETIC-PROPERTIES;    DOUBLE PEROVSKITES;    CRYSTAL-GROWTH;    PHASE;   

DOI  :  10.1103/PhysRevB.91.045133

来源: SCIE

【 摘 要 】

The double perovskite Ba2NaOsO6 (BNOO), an exotic example of a very high oxidation state (heptavalent) osmium d(1) compound and also uncommon by being a ferromagnetic open d-shell (Mott) insulator without Jahn-Teller (JT) distortion, is modeled using a density functional theory based hybrid functional incorporating exact exchange for correlated electronic orbitals and including the large spin-orbit coupling (SOC). The experimentally observed narrow-gap ferromagnetic insulating ground state is obtained, but only when including spin-orbit coupling, making this a Dirac-Mott insulator. The calculated easy axis along [110] is in accord with experiment, providing additional support that this approach provides a realistic method for studying this system. The predicted spin density for [110] spin orientation is nearly cubic (unlike for other directions), providing an explanation for the absence of JT distortion. An orbital moment of -0.4 mu(B) strongly compensates the +0.5 mu(B) spin moment on Os, leaving a strongly compensated moment more in line with experiment. Remarkably, the net moment lies primarily on the oxygen ions. An insulator-metal transition, by rotating the magnetization direction with an external field under moderate pressure, is predicted as one consequence of strong SOC, and metallization under moderate pressure is predicted. Comparison is made with the isostructural, isovalent insulator Ba2LiOsO6, which, however, orders antiferromagnetically.

【 授权许可】

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