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TT: Fachverband Tiefe Temperaturen

TT 77: Frustrated Magnets: Strong Spin-Orbit Coupling II

TT 77.6: Talk

Thursday, March 21, 2024, 16:15–16:30, H 3025

Metallic conductivity on Na-deficient structural domain walls in the spin-orbit Mott insulator Na₂IrO₃ — •Franziska Breitner, Julian Kaiser, Anton Jesche, and Philipp Gegenwart — Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany

Charge carrier doping of spin-orbit Mott insulators and Kitaev magnets is considered as promising route towards the realization of exotic quantum phases. Here we focus on the prototypical system Na₂IrO₃, for which previous ARPES and STM studies revealed indications of a high tunability of its electronic properties. We thus performed a combined structural and electrical resistivity study of Na₂IrO₃ single crystals [1]. Laue back-scattering diffraction indicates twinning with ± 120^∘ rotation around the c^*-axis while scanning electron microscopy displays nanothin lines parallel to all three b-axis orientations of twin domains. Energy dispersive x-ray analysis line-scans across such domain walls indicate no change of the Ir signal intensity, i.e. intact honeycomb layers, while the Na intensity is reduced down to ∼ 2/3 of its original value at the domain walls, implying significant hole doping. The temperature dependent electrical resistance of individual domain walls contacted via focused-ion-beam microstructuring demonstrates the tuning through the metal-insulator transition into a correlated-metal ground state by increasing hole doping.

[1] F. A. Breitner, J. Kaiser, A. Jesche, Ph. Gegenwart, https://arxiv.org/abs/2311.07275

Keywords: Mott insulator; Kitaev; structural domain walls