Observation of excitons bound by antiferromagnetic correlations

Abstract

Two-dimensional Mott insulators host antiferromagnetic (AFM) correlations that are predicted to enhance the attractive interaction between empty (holons) and doubly occupied (doublons) sites, creating a novel pathway for exciton formation. However, experimental confirmation of this spin-mediated binding mechanism remains elusive. Leveraging the distinct magnetic critical properties of the Mott antiferromagnets Sr${}_2$IrO${}_4$ and Sr${}_3$Ir${}_2$O${}_7$, we show using time-resolved THz spectroscopy that excitons only exist at temperatures below where short-range AFM correlation develops. The excitons remain stable up to photodoping densities approaching the predicted excitonic Mott insulator-to-metal transition, revealing a unique robustness against screening. Our results establish the viability of spin-bound excitons and introduce opportunities for excitonic control through magnetic degrees of freedom.

14 pages main text, 4 figures, 16 pages supplementary information

References in corpus (39)

• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Isospin Dynamics in Sr2IrO4 : Forging Links to Cuprate Superconductivity
• Twisted Hubbard Model for Sr2IrO4: Magnetism and Possible High Temperature Superconductivity
• Observation of a $d$-wave gap in electron-doped Sr${}_2$IrO${}_4$
• Ultrafast and reversible control of the exchange interaction in Mott insulators
• Imaging magnetic polarons in the doped Fermi-Hubbard model
• String patterns in the doped Hubbard model
• Two-dimensional Heisenberg behavior of Jeff = 1/2 isospins in the paramagnetic state of spin-orbital Mott insulator Sr2IrO4
• Anomalously Strong Near-Neighbor Attraction in Doped 1D Cuprate Chains
• Giant Magnon Gap in Bilayer Iridate Sr3Ir2O7: Enhanced Pseudo-dipolar Interactions Near the Mott Transition
• Ultrafast charge recombination in photoexcited Mott-Hubbard insulator
• Two-magnon Raman scattering and pseudospin-lattice interactions in Sr2IrO4 and Sr3Ir2O7
• Coupling a mobile hole to an antiferromagnetic spin background: Transient dynamics of a magnetic polaron
• Pseudospin-lattice coupling in the spin-orbit Mott insulator Sr2IrO4
• Strong pairing in mixed dimensional bilayer antiferromagnetic Mott insulators
• Confinement-Deconfinement Transition as an Indication of Spin-Liquid-Type Behavior in Na${}_2$IrO${}_3$
• Hubbard exciton revealed by time-domain optical spectroscopy
• Evidence of quantum dimer excitations in Sr${}_3$Ir${}_2$O${}_7$
• Theoretical study of insulating mechanism in multi-orbital Hubbard models with a large spin-orbit coupling: Slater versus Mott scenario in Sr${}_2$IrO${}_4$
• Spectroscopic evidence for polaronic behaviour of the strong spin-orbit insulator Sr${}_3$Ir${}_2$O${}_7$
• Charge Recombination in Undoped Cuprates
• First-order melting of a weak spin-orbit Mott insulator into a correlated metal
• Mott-Hubbard exciton in the optical conductivity of YTiO3 and SmTiO3
• Orbital Floquet Engineering of Exchange Interactions in Magnetic Materials
• Excitons in Mott insulators
• Antiferromagnetic Excitonic Insulator State in Sr3Ir2O7
• Spin-orbit-enhanced magnetic surface second-harmonic generation in Sr${}_2$IrO${}_4$
• Pairing of holes by confining strings in antiferromagnets
• Influence of spin and orbital fluctuations on Mott-Hubbard exciton dynamics in LaVO${}_3$ Thin Films
• A Hubbard exciton fluid in a photo-doped antiferromagnetic Mott insulator
• Exciton Recombination in One-Dimensional Organic Mott Insulators
• Spin-Mediated Mott Excitons
• Stability of High-Density Two-Dimensional Excitons against a Mott Transition in High Magnetic Fields Probed by Coherent Terahertz Spectroscopy
• Density-matrix renormalization group study of optical conductivity of the Mott insulator for two-dimensional clusters
• Dichotomy of heavy and light pairs of holes in the $t-J$ model
• Exciton condensation in bilayer spin-orbit insulator
• Magnetic order, disorder, and excitations under pressure in the Mott insulator Sr${}_2$IrO${}_4$
• Critical fluctuations in the spin-orbit Mott insulator Sr${}_3$Ir${}_2$O${}_7$
• Evolution of the spectral lineshape at the magnetic transition in Sr2IrO4 and Sr3Ir2O7

Cited by in corpus (1)

• Characteristic exciton energy scales in antiferromagnetic NiPS${}_3$