ARPES study of orbital characters, symmetry breakings and pseudogaps in doped and pure Sr2IrO4

Abstract

Sr2IrO4 is characterized by a large spin-orbit coupling, which gives rise to bands with strongly entangled spin and orbital characters, called J=1/2 and J=3/2. We use light-polarization dependent ARPES to study directly the orbital character of these bands and fully map out their dispersion. We observe bands in very good agreement with our cluster dynamical mean-field theory calculations. We show that the J=1/2 band, the closest to the Fermi level Ef, is dominated by dxz character along kx and dyz along ky. This is actually in agreement with an isotropic J=1/2 character on average, but this large orbital dependence in k-space was mostly overlooked before. It gives rise to strong modulations of the ARPES intensity that we explain and carefully take into account to compare dispersions in equivalent directions of the Brillouin zone. Although the latter dispersions look different at first, suggesting possible symmetry breakings, they are found essentially similar, once corrected for these intensity variations. In particular, the pseudogap-like features close to the $X$ point appearing in the nearly metallic 15% Rh-doped Sr2IrO4 strongly depend on experimental conditions. We reveal that there is nevertheless an energy scale of 30meV below which spectral weight is suppressed, independent of the experimental conditions, which gives a reliable basis to analyze this behavior. We suggest it is caused by disorder.

References in corpus (25)

• Angle-resolved photoemission spectroscopy of the cuprate superconductors
• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Fermi Arcs in a Doped Pseudospin-1/2 Heisenberg Antiferromagnet
• Evidence for incommensurate spin fluctuations in Sr_2RuO_4
• The Electronic Nature of High Temperature Cuprate Superconductors
• Reduced effective spin-orbital degeneracy and spin-orbital ordering in paramagnetic transition metal oxides: Sr2IrO4 vs. Sr2RhO4
• Evidence of an odd-parity hidden order in a spin-orbit coupled correlated iridate
• Collapse of the Mott gap and emergence of a nodal liquid in lightly doped Sr${}_2$IrO${}_4$
• Enhanced Crystal Field Splitting and Orbital Selective Coherence by Strong Correlations in V_2O_3
• Spin-Orbit Integrated Ground State and Magnetic Anisotropy in Sr${}_2$IrO${}_4$
• Coulomb-Enhanced Spin-Orbit Splitting: The Missing Piece in the Sr2RhO4 Puzzle
• Dilute Magnetism and Spin-Orbital Percolation Effects in Rh-doped Sr2IrO4
• Coulomb Correlations in 4d and 5d Oxides from First Principles - or How Spin-Orbit Materials choose their Effective Orbital Degeneracies
• Orbital reconstruction in nonpolar tetravalent transition-metal oxide layers
• Time-reversal symmetry breaking hidden order in Sr${}_2$(Ir,Rh)O${}_4$
• Transfer of spectral weight across the gap of Sr2IrO4 induced by La doping
• A charge density wave-like instability in a doped spin-orbit-assisted weak Mott insulator
• Unidirectional spin density wave state in metallic (Sr1-xLax)2IrO4
• Correlation effects and hidden spin-orbit entangled electronic order in parent and electron-doped iridates Sr${}_2$IrO${}_4$
• Spectral functions of Sr${}_2$IrO${}_4$: theory versus experiment
• Formation of an incoherent metallic state in Rh-doped Sr${}_2$IrO${}_4$
• Non-local Coulomb correlations in pure and electron-doped ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$: spectral functions, Fermi surface and pseudogap-like spectral weight distributions from oriented cluster dynamical mean field theory
• Pseudogap and electronic structure of electron-doped Sr${}_2$IrO${}_4$
• Ultrafast filling of an electronic pseudogap in an incommensurate crystal

Cited by in corpus (7)

• Light-induced insulator-metal transition in Sr${}_2$IrO${}_4$ reveals the nature of the insulating ground state
• Origin of the different electronic structure of Rh- and Ru-doped Sr2IrO4
• Band unfolding with a general transformation matrix: from code implementation to interpretation of photoemission spectra
• The rich phase diagram of the prototypical iridate Ba${}_2$IrO${}_4$: Effective low-energy models and metal-insulator transition
• The "dark phase'' in Sr${}_2$Ir${}_{1-x}$Rh${}_x$O${}_4$ revealed by Seebeck and Hall measurements
• Orbital-Selective Spin-Orbit Mott Insulator in Fractional Valence Iridate La${}_3$Ir${}_3$O${}_{11}$
• Formation of CuO${}_2$ sublattices by suppression of interlattice correlations in tetragonal CuO