Spin-orbit tuned metal-insulator transitions in single-crystal Sr 2Ir1-xRhxO4 (0 ≤ x ≤ 0.16)

T. F. Qi, O. B. Korneta, L. Li, K. Butrouna, V. S. Cao, Xiangang Wan, P. Schlottmann, R. K. Kaul, G. Cao

Research output: Contribution to journalArticlepeer-review

103 Scopus citations

Abstract

Sr2IrO4 is a magnetic insulator driven by spin-orbit interaction (SOI) whereas the isoelectronic and isostructural Sr 2RhO4 is a paramagnetic metal. The contrasting ground states have been shown to result from the critical role of the strong SOI in the iridate. Our investigation of structural, transport, magnetic, and thermal properties reveals that substituting 4d Rh4+ (4d5) ions for 5d Ir4+ (5d5) ions in Sr2IrO4 directly reduces the SOI and rebalances the competing energies so profoundly that it generates a rich phase diagram for Sr2Ir1-xRhxO4 featuring two major effects: (1) Light Rh doping (0 ≤ x ≤ 0.16) prompts a simultaneous and precipitous drop in both the electrical resistivity and the magnetic ordering temperature TC, which is suppressed to zero at x = 0.16 from 240 K at x = 0. (2) However, with heavier Rh doping [0.24 < x < 0.85 (±0.05)] disorder scattering leads to localized states and a return to an insulating state with spin frustration and exotic magnetic behavior that only disappears near x = 1. The intricacy of Sr2Ir 1-xRhxO4 is further highlighted by comparison with Sr2Ir1-xRuxO4 where Ru4 + (4d4) drives a direct crossover from the insulating to metallic states.

Original languageEnglish
Article number125105
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number12
DOIs
StatePublished - Sep 6 2012

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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