Disordered dimer state in electron-doped Sr${}_3$Ir${}_2$O${}_7$

Abstract

Spin excitations are explored in the electron-doped spin-orbit Mott insulator (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$. As this bilayer square lattice system is doped into the metallic regime, long-range antiferromagnetism vanishes, yet a spectrum of gapped spin excitation remains. Excitation lifetimes are strongly damped with increasing carrier concentration, and the energy integrated spectral weight becomes nearly momentum independent as static spin order is suppressed. Local magnetic moments, absent in the parent system, grow in metallic samples and approach values consistent with one $J=\frac{1}{2}$ impurity per electron doped. Our combined data suggest that the magnetic spectra of metallic (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$ are best described by excitations out of a disordered dimer state.

6 pages, 4 figures; 8 pages of supplementary material included as ancillary file

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Cited by in corpus (13)

• A charge density wave-like instability in a doped spin-orbit-assisted weak Mott insulator
• Strain-engineering of the charge and spin-orbital interactions in Sr2IrO4
• Doping Evolution of Magnetic Order and Magnetic Excitations in (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$
• Antiferromagnetic Excitonic Insulator State in Sr3Ir2O7
• Symmetry-resolved two-magnon excitations in a strong spin-orbit-coupled bilayer antiferromagnet
• Resonant inelastic x-ray scattering of magnetic excitations under pressure
• Exciton condensation in bilayer spin-orbit insulator
• Overdamped antiferromagnetic strange metal state in Sr${}_3$IrRuO${}_7$
• Doping driven structural distortion in the bilayer iridate (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$
• Carrier dynamics in doped bilayer iridates near magnetic quantum criticality
• Electron doping in ${\text{Sr}}_3{\text{Ir}}_2{\text{O}}_7$: collapse of band gap and magnetic order
• Sr${}_3$Ir${}_2$O${}_7$F${}_2$: Topochemical conversion of a relativistic Mott state into a spin-orbit driven band insulator
• Putative magnetic quantum criticality in (Sr${}_{\text{1-x}}$La${}_{\text{x}}$)${}_{\text{3}}$Ir${}_{\text{2}}$O${}_{\text{7}}$