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arXiv · 1810.02942

Sr$_3$Ir$_2$O$_7$F$_2$: Topochemical conversion of a relativistic Mott state into a spin-orbit driven band insulator

Christi Peterson·Michael W. Swift·Zach Porter·Raphaele J. Clement·Guang Wu·G. H. Ahn·S. J. Moon·B. C. Chakoumakos·Jacob P. C. Ruff·Huibo Cao·Chris Van de Walle·Stephen D. Wilson
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Abstract

The topochemical transformation of single crystals of Sr$_3$Ir$_2$O$_7$ into Sr$_3$Ir$_2$O$_7$F$_2$ is reported via fluorine insertion. Characterization of the newly formed Sr$_3$Ir$_2$O$_7$F$_2$ phase shows a nearly complete oxidation of Ir$^{4+}$ cations into Ir$^{5+}$ that in turn drives the system from an antiferromagnetic Mott insulator with a half-filled J$_{eff}=1/2$ band into a nonmagnetic $J=0$ band insulator. First principles calculations reveal a remarkably flat insertion energy that locally drives the fluorination process to completion. Band structure calculations support the formation of a band insulator whose charge gap relies on the strong spin-orbit coupling inherent to the Ir metal ions of this compound.

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Christi Peterson, Michael W. Swift, Zach Porter, Raphaele J. Clement, Guang Wu, G. H. Ahn, S. J. Moon, B. C. Chakoumakos, Jacob P. C. Ruff, Huibo Cao, Chris Van de Walle, Stephen D. Wilson. 2018-10-06. Sr$_3$Ir$_2$O$_7$F$_2$: Topochemical conversion of a relativistic Mott state into a spin-orbit driven band insulator. https://doi.org/10.1103/physrevb.98.155128

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