Evolution of structure and magnetism across the metal-insulator transition in the pyrochlore iridate (Nd1-x Cax)2 Ir2 O7
Physical Review B
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We report on the evolution of the thermal metal-insulator transition in polycrystalline samples of Nd2Ir2O7 upon hole doping via substitution of Ca2+ for Nd3+. Ca substitution mediates a filling-controlled Mott-like transition with minimal resolvable structural changes and without altering site symmetry. Local structure confirms that Ca substitution does not result in local chemical phase separation, and absorption spectroscopy establishes that Ir cations maintain a spin-orbit entangled electronic configuration. The metal-insulator transition coincides with antiferromagnetic ordering on the Ir sublattice for all measured samples, and both decrease in onset temperature with Ca content. Weak low-temperature upturns in susceptibility and resistivity for samples with high Ca content suggest that Nd sublattice antiferromagnetism continues to couple to carriers in the metallic regime.
Z. Porter, E. Zoghlin, S. Britner, S. Husremovic, J. P. C. Ruff, Y. Choi, D. Haskel, G. Laurita, and S. Wilson, Evolution of structure and magnetism across the metal-insulator transition in the pyrochlore iridate (Nd1-xCax)2Ir2O7, Phys. Rev. B. 100 (2019) 054409. https://doi.org/10.1103/PhysRevB.100.054409
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© American Physical Society. All rights reserved. Original version is available from the publisher at: https://doi.org/10.1103/PhysRevB.100.054409