Decoupling of the magnetic and insulating states in single-crystal (Sr<sub>1-x</sub>A<sub>x</sub>)<sub>2</sub>IrO<sub>4</sub> (A=Ca or Ba)

ORAL

Abstract

Sr2IrO4 is the archetype Jeff=1/2 Mott insulator with a Néel temperature TN = 240 K and an energy gap of 0.62 eV. Here we report results of our recent study of Ca or Ba doped Sr2IrO4. Substituting Ca2+ (up to 15%) or Ba2+ (up to 3%) ion for the Sr2+ ion provides no additional charge carriers, but alters the lattice parameters and reduces IrO6 octahedra distortions in Sr2IrO4. This study reveals that Ca or Ba doping retains the Néel temperature, however, drastically reduces the electrical resistivity by more than five orders of magnitude or even precipitates a sharp insulator-to-metal transition at lower temperatures. In essence, the vanishing insulating state due to Ca or Ba doping is accompanied by an unchanged Néel temperature. This study provides strong evidence that there is an unusual correlation between the magnetic and insulating state in this spin-orbit tuned insulator.

*This work was supported by the National Science Foundation via grant DMR-1712101.

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Presenters

  • Jasminka Terzic

    • Univ of Kentucky
    • National High Magnetic Field Laboratory
    • Department of Physics, Univ of Colorado - Boulder
    • University of Colorado at Boulder

Authors

  • Jasminka Terzic

    • Univ of Kentucky
    • National High Magnetic Field Laboratory
    • Department of Physics, Univ of Colorado - Boulder
    • University of Colorado at Boulder

  • Hengdi Zhao

    • Department of Physics, Univ of Colorado - Boulder
    • Department of Physics, University of Colorado
    • University of Colorado at Boulder

  • Hao Zheng

    • Department of Physics, Univ of Colorado - Boulder
    • Department of Physics, University of Colorado
    • University of Colorado at Boulder

  • Wenhai Song

    • Institute of Solid State Physics, Chinese Academy of Science
    • Department of Physics, Univ of Colorado - Boulder

  • Yifei Ni

    • Department of Physics, Univ of Colorado - Boulder
    • Department of Physics, University of Colorado

  • Yu Zhang

    • Department of Physics, Univ of Colorado - Boulder
    • Department of Physics, University of Colorado

  • Gang Cao

    • Physics, Univ of Colorado - Boulder
    • Department of Physics, University of Colorado-Boulder
    • Department of Physics, University of Colorado Boulder
    • Materials Science and Engineering Program, University of Colorado Boulder
    • Department of Physics, Univ of Colorado - Boulder
    • Department of Physics, University of Colorado
    • University of Colorado at Boulder