Three-dimensional electronic structures and the metal-insulator transition in Ruddlesden-Popper iridates

Abstract

In this study, we systematically investigate 3D momentum($\hslash k$)-resolved electronic structures of Ruddlesden-Popper-type iridium oxides Sr${}_{n+1}$Ir${}_n$O${}_{3n+1}$ using soft-x-ray (SX) angle-resolved photoemission spectroscopy (ARPES). Our results provide direct evidence of an insulator-to-metal transition that occurs upon increasing the dimensionality of the IrO${}_2$-plane structure. This transition occurs when the spin-orbit-coupled $j_{\mathrm{eff}}$=1/2 band changes its behavior in the dispersion relation and moves across the Fermi energy. In addition, an emerging band along the $\Gamma$(0,0,0)-R($\pi$,$\pi$,$\pi$) direction is found to play a crucial role in the metallic characteristics of SrIrO${}_3$. By scanning the photon energy over 350 eV, we reveal the 3D Fermi surface in SrIrO${}_3$ and $k_z$-dependent oscillations of photoelectron intensity in Sr${}_3$Ir${}_2$O${}_7$. In contrast to previously reported results obtained using low-energy photons, folded bands derived from lattice distortions and/or magnetic ordering make significantly weak (but finite) contributions to the $k$-resolved photoemission spectrum. At the first glance, this leads to the ambiguous result that the observed $k$-space topology is consistent with the unfolded Brillouin zone (BZ) picture derived from a non-realistic simple square or cubic Ir lattice. Through careful analysis, we determine that a superposition of the folded and unfolded band structures has been observed in the ARPES spectra obtained using photons in both ultraviolet and SX regions. To corroborate the physics deduced using low-energy ARPES studies, we propose to utilize SX-ARPES as a powerful complementary technique, as this method surveys more than one whole BZ and provides a panoramic view of electronic structures.

arXiv comment16 pages, 12 figures, 4 tables

References in corpus (23)

• Quantum Spin Hall Effect in Graphene
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Bandwidth-Controlled Insulator-Metal Transition and Correlated Metallic State in 5$d$ Transition Metal Oxides Sr${}_{n+1}$Ir${}_n$O${}_{3n+1}$ ($n$=1, 2, and $\infty$)
• Fermi Arcs in a Doped Pseudospin-1/2 Heisenberg Antiferromagnet
• Semimetal and Topological Insulator in Perovskite Iridates
• Interplay of Spin-Orbit Interactions, Dimensionality, and Octahedral Rotations in Semimetallic SrIrO${}_3$
• Monte Carlo study of an unconventional superconducting phase in Ir-oxide J_{eff}=1/2 Mott insulators induced by carrier doping
• Engineering spin-orbital magnetic insulator by tailoring superlattices
• Microscopic study of spin-orbit-induced Mott insulator in Ir oxides
• Collapse of the Mott gap and emergence of a nodal liquid in lightly doped Sr${}_2$IrO${}_4$
• Interplay between spin-orbit coupling and Hubbard interaction in SrIrO3 and related Pbnm perovskites
• Direct observation of the Dirac nodes lifting in semimetallic perovskite SrIrO3 thin films
• Dimensionality controlled Mott transition and correlation effects in single- and bi-layer perovskite iridates
• Technique for bulk Fermiology by photoemission applied to layered ruthenates
• Doped Mott Insulators in (111) Bilayers of Perovskite Transition-Metal Oxides with a Strong Spin-Orbit Coupling
• Theory of magnetism and metal-insulator transition in layered perovskite iridates
• Weak antiferromagnetism of J_eff=1/2 band in bilayer iridate Sr3Ir2O7
• Surface States of Perovskite Iridates AIrO${}_3$; Signatures of Topological Crystalline Metal with Nontrivial ${\mathbb{Z}}_2$ Index
• Spectroscopic evidence for polaronic behaviour of the strong spin-orbit insulator Sr${}_3$Ir${}_2$O${}_7$
• Electron correlation in FeSe superconductor studied by bulk-sensitive photoemission spectroscopy
• Nature of the Electronic Excitations near the Brillouin Zone Boundary of Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$
• Correlated vs. conventional insulating behavior in the Jeff=1/2 vs. 3/2 bands in the layered iridate Ba2IrO4
• Microscopic theory of magnetism in Sr3Ir2O7

Cited by in corpus (11)

• Dimensionality-driven metal-insulator-transition in spin-orbit coupled SrIrO${}_3$
• Relativistic $GW$+BSE study of the optical properties of Ruddlesden-Popper iridates
• Review of Spin Orbit Coupled Semimetal SrIrO3 in thin film form
• Dimensionality-strain phase diagram of strontium iridates
• Weakly-correlated nature of ferromagnetism in non symmorphic CrO${}_2$ revealed by bulk-sensitive soft X ray ARPES
• Correlation induced electron-hole asymmetry in quasi-2D iridates
• Evolution of remnant Fermi surface state in lightly-doped correlated spin-orbit insulator Sr${}_{2-x}$La${}_x$IrO${}_4$
• Influence of multiplet structure on photoemission spectra of spin-orbit driven Mott insulators: application to $\mathbf{S}{\mathbf{r}}_2\mathbf{Ir}{\mathbf{O}}_4$
• Determination of the local structure of Sr${}_{2-x}$M${}_x$IrO${}_4$ (M = K, La) as a function of doping and temperature
• Possible superconductivity induced by a large spin-orbit coupling in carrier doped iridium oxide insulators: A weak coupling approach
• Fingerprints of Mott and Slater gaps in the core-level photoemission spectra of antiferromagnetic iridates