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

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 $c^{\ast }$-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.

8 pages, 9 figures

References in corpus (9)

• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Models and Materials for Generalized Kitaev Magnetism
• Quantum spin Hall effect in a transition metal oxide Na2IrO3
• Crystal field splitting and correlation effect on the electronic structure of A2IrO3
• Na2IrO3 as a spin-orbit-assisted antiferromagnetic insulator with a 340 meV gap
• Microscopic study of spin-orbit-induced Mott insulator in Ir oxides
• Magnetic avalanche of non-oxide conductive domain walls
• Investigation of unconventional reconstruction and electronic properties on the Na2IrO3 surface
• Quasiparticles and charge transfer at the two surfaces of the honeycomb iridate Na${}_2$IrO${}_3$