Ab initio investigations of the Ca2IrO4-type structure as a “post-K2NiF4”: Case study of Na2OsO4

Deriving the energy–volume equation of state for Na2OsO4 in its actual Ca2IrO4-type structure at high pressure and in hypothetic K2NiF4-type, leads to energy destabilization at a larger volume for the latter and to propose the former as a post-K2NiF4 through which a tuning of the magnetism and conductivity can be achieved: while the oxide system is magnetically silent in Ca2IrO4-type due to spin pairing (S = 0 for d2 Os6+) with a semi-conducting behavior, a finite moment develops in the latter when spin polarization is accounted for (S = 1).

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