A charge density wave-like instability in a doped spin-orbit-assisted weak Mott insulator

Abstract

Layered perovskite iridates realize a rare class of Mott insulators that are predicted to be strongly spin-orbit coupled analogues of the parent state of cuprate high-temperature superconductors. Recent discoveries of pseudogap, magnetic multipolar ordered and possible $d$-wave superconducting phases in doped Sr${}_2$IrO${}_4$ have reinforced this analogy among the single layer variants. However, unlike the bilayer cuprates, no electronic instabilities have been reported in the doped bilayer iridate Sr${}_3$Ir${}_2$O${}_7$. Here we show that Sr${}_3$Ir${}_2$O${}_7$ realizes a weak Mott state with no cuprate analogue by using ultrafast time-resolved optical reflectivity to uncover an intimate connection between its insulating gap and antiferromagnetism. However, we detect a subtle charge density wave-like Fermi surface instability in metallic electron doped Sr${}_3$Ir${}_2$O${}_7$ at temperatures ($T_{DW}$) close to 200 K via the coherent oscillations of its collective modes, which is reminiscent of that observed in cuprates. The absence of any signatures of a new spatial periodicity below $T_{DW}$ from diffraction, scanning tunneling and photoemission based probes suggests an unconventional and possibly short-ranged nature of this density wave order.

13 pages main text, 4 figures, 10 pages supplementary information, in Nature Materials (2017)

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Cited by in corpus (27)

• The Challenge of Spin-Orbit-Tuned Ground States in Iridates
• Phase-resolved Higgs response in superconducting cuprates
• Charge order and antiferromagnetism in the extended Hubbard model
• Laser-Induced Transient Magnons in Sr3Ir2O7 Throughout the Brillouin Zone
• Strong Pseudospin-Lattice Coupling in Sr3Ir2O7: Coherent Phonon Anomaly and Negative Thermal Expansion
• Novel spin-orbit coupling driven emergent states in iridate-based heterostructures
• Evidence of an improper displacive phase transition in Cd${}_2$Re${}_2$O${}_7$ via time-resolved coherent phonon spectroscopy
• Fano interference of the Higgs mode in cuprate high-Tc superconductors
• Evolution of Magnetic Excitations Across the Metal-Insulator Transition in a Pyrochlore Iridate Eu${}_2$Ir${}_2$O${}_7$
• Lattice frustration in spin-orbit Mott insulator Sr3Ir2O7 at high pressure
• ARPES study of orbital characters, symmetry breakings and pseudogaps in doped and pure Sr2IrO4
• Giant photoinduced lattice distortion in oxygen-vacancy ordered SrCoO2.5 thin films
• Symmetry-resolved two-magnon excitations in a strong spin-orbit-coupled bilayer antiferromagnet
• Doping driven structural distortion in the bilayer iridate (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$
• Momentum-resolved lattice dynamics of parent and electron-doped Sr${}_2$IrO${}_4$
• Determination of the local structure of Sr${}_{2-x}$M${}_x$IrO${}_4$ (M = K, La) as a function of doping and temperature
• Study of pseudogap and superconducting quasiparticle dynamics in $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{r}}_2\mathrm{CaC}{\mathrm{u}}_2{\mathrm{O}}_{8+\delta }$ by time-resolved optical reflectivity
• Polarized Raman spectroscopy study of metallic $(S{r}_{1-x}L{a}_x{)}_{3}I{r}_2{O}_7$: a consistent picture of disorder-interrupted unidirectional charge order
• Ultrafast dynamics in the Lifshitz-type 5$d$ pyrochlore antiferromagnet Cd${}_2$Os${}_2$O${}_7$
• Pump-induced terahertz conductivity response and peculiar bound state in Mn3Si2Te6
• Quasiparticle Relaxation Dynamics in URu${}_{2-x}$Fe${}_x$Si${}_2$ Single Crystals
• Electron doping in ${\text{Sr}}_3{\text{Ir}}_2{\text{O}}_7$: collapse of band gap and magnetic order
• Photoinduced two-step insulator-metal transition in Ti4O7 by ultrafast time-resolved optical reflectivity
• Melting of magnetic order in ${\mathrm{NaOsO}}_3$ by fs laser pulses
• Putative magnetic quantum criticality in (Sr${}_{\text{1-x}}$La${}_{\text{x}}$)${}_{\text{3}}$Ir${}_{\text{2}}$O${}_{\text{7}}$
• Absence of temperature-dependent phonon anomalies in Sr2IrO4 and Sr3Ir2O7
• Ultrafast Dynamics of Spin-Orbit Entangled Excitons Coupled to Magnetic Ordering in van der Waals Antiferromagnet NiPS3