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arXiv · 2311.07275

Metallic conductivity on Na-deficient structural domain walls in the spin-orbit Mott insulator Na$_2$IrO$_3$

Franziska A. Breitner·Julian Kaiser·Anton Jesche·Philipp Gegenwart
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Abstract

Honeycomb Na$_2$IrO$_3$ is a prototype spin-orbit Mott insulator and Kitaev magnet. We report a combined structural and electrical resistivity study of Na$_2$IrO$_3$ single crystals. Laue back-scattering diffraction indicates twinning with $\pm 120^\circ$ 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 $\sim 2/3$ of its original value at the domain walls, implying significant hole doping. Utilizing focused-ion-beam micro-sectioning, the temperature dependence of the electrical resistance of individual domain walls is studied. It demonstrates the tuning through the metal-insulator transition into a correlated-metal ground state by increasing hole doping.

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Franziska A. Breitner, Julian Kaiser, Anton Jesche, Philipp Gegenwart. 2023-11-13. Metallic conductivity on Na-deficient structural domain walls in the spin-orbit Mott insulator Na$_2$IrO$_3$. https://doi.org/10.1103/physrevb.108.235130

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