2 research outputs found
Observation of exciton redshift-blueshift crossover in monolayer WS2
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 inter-particle
interaction, which holds promise to pursue the predicted liquid and crystalline
phases of excitons in two-dimensional materials