Observation of Exciton Redshift–Blueshift Crossover in Monolayer WS₂
Author(s)Sie, Edbert Jarvis; Steinhoff, A.; Gies, C.; Lui, C. H.; Ma, Qing; Rösner, M.; Schönhoff, G.; Jahnke, F.; Wehling, T. O.; Lee, Y.-H.; Kong, Jian Feng; Jarillo-Herrero, Pablo; Gedik, Nuh; ... Show more Show less
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We report a rare atom-like interaction between excitons in monolayer WS₂, measured using ultrafast absorption spectroscopy. At increasing excitation density, the exciton resonance energy exhibits a pronounced redshift followed by an anomalous blueshift. Using both material-realistic computation and phenomenological modeling, we attribute this observation to plasma effects and an attraction-repulsion crossover of the exciton-exciton interaction that mimics the Lennard-Jones potential between atoms. Our experiment demonstrates a strong analogy between excitons and atoms with respect to interparticle interaction, which holds promise to pursue the predicted liquid and crystalline phases of excitons in two-dimensional materials.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
American Chemical Society (ACS)
Sie, E. J. et al. “Observation of Exciton Redshift–Blueshift Crossover in Monolayer WS₂.” Nano Letters 17, 7 (June 2017): 4210–4216 © 2017 American Chemical Society
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