Characterization of a Potential Low-Dimensional Kitaev Chain Compound: Yttrium-Doped Calcium Iridate, Ca_5-xY_xIr₃O₁₂

Exchange frustration resulting from Kitaev interactions can lead to the emergence of quantum spin liquid states. Experimental realizations of materials with dominant Kitaev interactions, particularly in lattice types beyond honeycomb, remain limited. However, from a materials design perspective, these interactions are expected to emerge in systems which possess: (1) a J_eff = 1/2 ground state, and (2) edge-sharing octahedral geometry. We propose yttrium-doped calcium iridate, Ca_5-xY_xIr₃O₁₂, as a promising candidate for hosting Kitaev interactions in a quasi-one-dimensional chain-like system. In this talk, we report on the synthesis and characterization of Ca_5-xY_xIr₃O₁₂ for x=0 to x~1.5. High-quality single crystals were synthesized across six doping levels, with the highest doping level x=1.52(2), significantly exceeding previous studies on Sr, La, Bi, and Na-doped Ca₅Ir₃O₁₂. This results in a tunable Ir valence range from 4.67+ to 4.16+. Our structural analysis, using single-crystal X-ray diffraction and high dynamic range reciprocal space mapping, reveals no change in space group up to x~1.5, but indicates that IrO6 octahedral cage becomes increasingly symmetrical as function of doping. Electronic characterization through HERFD-XAS confirms the tuning of Ir valence with doping and is consistent with a spin-orbit-driven J_eff state across all synthesized samples. Magnetic susceptibility measurements reveal a rapid suppression of magnetic order at low dopings, with the emergence of a new magnetically ordered ground state at higher dopings.