Quasiparticles and charge transfer at the two surfaces of the honeycomb iridate Na${}_2$IrO${}_3$

Abstract

Direct experimental investigations of the low-energy electronic structure of the Na${}_2$IrO${}_3$ iridate insulator are sparse and draw two conflicting pictures. One relies on flat bands and a clear gap, the other involves dispersive states approaching the Fermi level, pointing to surface metallicity. Here, by a combination of angle-resolved photoemission, photoemission electron microscopy, and x-ray absorption, we show that the correct picture is more complex and involves an anomalous band, arising from charge transfer from Na atoms to Ir-derived states. Bulk quasiparticles do exist, but in one of the two possible surface terminations the charge transfer is smaller and they remain elusive.

References in corpus (12)

• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• On the Origin of Zigzag Magnetic Order in Iridium Oxide Na2IrO3
• Quantum spin Hall effect in a transition metal oxide Na2IrO3
• Long range magnetic ordering in Na${}_2$IrO${}_3$
• Fermi Arcs in a Doped Pseudospin-1/2 Heisenberg Antiferromagnet
• A precise method for visualizing dispersive features in image plots
• 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
• Confinement-Deconfinement Transition as an Indication of Spin-Liquid-Type Behavior in Na${}_2$IrO${}_3$
• Spectroscopic evidence for negative electronic compressibility in a quasi-three-dimensional spin-orbit correlated metal
• A weakly correlated Fermi liquid state with a small Fermi surface in lightly doped Sr${}_3$Ir${}_2$O${}_7$
• Investigation of unconventional reconstruction and electronic properties on the Na2IrO3 surface

Cited by in corpus (6)

• Competition between magnetic order and charge localization in Na${}_2$IrO${}_3$ thin crystal devices
• Topological property of a $t_{2g}^5$ system with a honeycomb lattice structure
• Spectrum of the hole excitation in spin-orbit Mott insulator Na${}_2$IrO${}_3$
• Electronic transport mechanisms in a thin crystal of the Kitaev candidate $\alpha$-RuCl${}_3$ probed through guarded high impedance measurements
• Enhanced Magnetism and Phase Transitions in Ultrathin Quantum Spin Liquid Na2IrO3 Flakes
• Metallic conductivity on Na-deficient structural domain walls in the spin-orbit Mott insulator Na${}_2$IrO${}_3$