Evolution of structure and magnetism across the metal-insulator transition in the pyrochlore iridate $($Nd${}_{1-x}$Ca${}_x{)}_2$Ir${}_2$O${}_7$

Abstract

We report on the evolution of the thermal metal-insulator transition in polycrystalline samples of Nd${}_2$Ir${}_2$O${}_7$ upon hole-doping via substitution of Ca${}^{2+}$ for Nd${}^{3+}$. 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.

10 pages, 7 figures

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Cited by in corpus (5)

• Spontaneous Hall Effect enhanced by local Ir moments in epitaxial Pr${}_2$Ir${}_2$O${}_7$ thin films
• Evolution of possible Weyl semimetal states across the hole-doping induced Mott transition in pyrochlore iridates
• Role of f-d exchange interaction and Kondo scattering in Nd doped pyrochlore Iridate (Eu1-xNdx)2Ir2O7
• Non-Fermi liquid regime in metallic pyrochlore iridates: Quantum Griffiths singularities
• Mapping the structural, magnetic and electronic behavior of (Eu${}_{1-x}$Ca${}_x$)${}_2$Ir${}_2$O${}_7$ across a metal-insulator transition