Honeycomb Na2IrO3 is a prototype spin-orbit Mott insulator and Kitaev magnet. We report a combined structural and electrical resistivity study of Na2IrO3 single crystals. 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. 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.
@article{arxiv.2311.07275,
title = {Metallic conductivity on Na-deficient structural domain walls in the spin-orbit Mott insulator Na$_2$IrO$_3$},
author = {Franziska A. Breitner and Julian Kaiser and Anton Jesche and Philipp Gegenwart},
journal= {arXiv preprint arXiv:2311.07275},
year = {2023}
}