Coupled Femtoexcitons, Free Carriers, and Light.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40769538.
- Also identified by DOI 10.1021/acs.nanolett.5c01871 and PMC identifier 12371882.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Nonequilibrium quantum matter generated by ultrafast laser light opens new pathways in fundamental condensed matter physics, as well as offering rich control possibilities in "tailoring matter by light". Here we explore the coupling between free carriers and excitons mediated by femtosecond-scale laser pulses. Employing monolayer WSe<sub>2</sub> and an <i>ab initio</i> treatment of pump-probe spectroscopy, we find that, counterintuitively, laser light resonant with the exciton can generate massive enhancement of the early-time free-carrier population. This exhibits a complex dynamical correlation to the excitons, with an oscillatory coupling between the free carrier population and exciton peak height that persists. Our results both unveil "femtoexcitons" as possessing rich femtosecond dynamics as well as, we argue, allow tailoring of early-time light-matter interaction via laser pulse design to control simultaneously excitonic and free-carrier physics at ultrafast times.