Cu2IrO3: a new honeycomb iridate material with an ideal lattice geometry for the Kitaev model

ORAL

Abstract

We present the first binary copper iridium oxide synthesized by a topotactic reaction from sodium iridate and copper chloride under mild conditions. Chemical analysis and crystallographic refinement reveal the composition Cu2IrO3 in a monoclinic C2/c space group with layered honeycomb structure. Magnetization measurements show a magnetic transition at low temperatures T = 2.75 K. The transition is subtle with weak hysteresis in the magnetization and without a clear signature in the heat capacity. The Curie-Weiss analysis reveals that the effective iridium magnetic moment and the exchange coupling strength in Cu2IrO3 are similar to its parent compound Na2IrO3. Resistivity measurements show insulator behavior with variable-range hopping. The frustration index f = 40 in Cu2IrO3 compared to 8 in Na2IrO3 brings copper iridate in closer proximity to a Kitaev spin liquid than its predecessors.

*The work at Boston College was supported by BC starting budget and NSF Grant No. DMR-5104811. The work at Harvard and CNS was supported by the STC Center for Integrated Quantum Materials, NSF Grant No. DMR-1231319.

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Presenters

  • Fazel Fallah Tafti

    • Physics, Boston College

Authors

  • Fazel Fallah Tafti

    • Physics, Boston College

  • Mykola Abramchuk

    • Boston College
    • Physics, Boston College

  • Cigdem Ozsoy-Keskinbora

    • School of Applied Sciences and Engineering, Harvard University
    • School of Engineering and Applied Sciences, Harvard University
    • Engineering and Applied Sciences, Harvard University

  • Jason Krizan

    • Physics, Boston College
    • Princeton University

  • Kenneth Metz

    • Physics, Boston College

  • David Bell

    • Applied physics, Harvard univeristy
    • Harvard Center for Nanoscale Systems
    • Engineering and Applied Sciences, Harvard University