Abstract
The simultaneous presence of sizable spin-orbit interactions and electron correlations in iridium oxides has led to predictions of novel ground states including Dirac semimetals, Kitaev spin liquids, and superconductivity. Electron and hole doping studies of spin-orbit assisted Mott insulator are being intensively pursued due to extensive parallels with the parent compound of cuprate superconductors. In particular, the mechanism of charge doping associated with replacement of Ir with Rh ions remains controversial with profound consequences for the interpretation of electronic structure and transport data. Using x-ray absorption near edge structure measurements at the Rh L, K, and Ir edges we observe anomalous evolution of charge partitioning between Rh and Ir with Rh doping. The partitioning of charge between Rh and Ir sites progresses in a way that holes are initially doped into the band at low only to be removed from it at higher values. This anomalous hole doping naturally explains the reentrant insulating phase in the phase diagram of and ought to be considered when searching for superconductivity and other emergent phenomena in iridates doped with elements.
- Received 23 November 2016
- Revised 25 January 2017
DOI:https://doi.org/10.1103/PhysRevB.95.060407
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