Observation of excitons bound by antiferromagnetic correlations

作     者：Omar Mehio Yuchen Han Xinwei Li Honglie Ning Zach Porter Stephen D. Wilson David Hsieh 

作者机构：Institute for Quantum Information and Matter California Institute of Technology Pasadena California 91125 USA Department of Physics California Institute of Technology Pasadena California 91125 USA Current address: Kavli Institute at Cornell for Nanoscale Science Cornell University Ithaca New York 14853 USA. Linac Coherent Light Source and Stanford Institute for Materials and Energy Sciences SLAC National Accelerator Laboratory Menlo Park California 94025 USA Materials Department University of California Santa Barbara California 93106 USA 

出 版 物：《Physical Review Research》 (Phys. Rev. Res.)

年 卷 期：2025年第7卷第1期

页      面：013114-013114页

核心收录：

基　　金：National Science Foundation, NSF, (DMR-2104833) NSF Physics Frontiers Center, (PHY-2317110, DMR-1729489) U.C. Santa Barbara NSF, (DMR-1906325) 

主　　题：Terahertz spectroscopy 

摘      要：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 Sr2IrO4 and Sr3Ir2O7, we show using time-resolved THz spectroscopy that excitons exist only 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.