Interactions of electrons and Rydberg excitons in two-dimensional semiconductors

Abstract: Rydberg excitons in two-dimensional semiconductors provide sensitive and non-destructive probes of physics in proximal sample layers that host correlated electronic states. In particular, electron or hole doping of the sample layer is heralded by a strong frequency shift and loss of transition strength of 2s excitons in the sensor layer; these features have been attributed to the formation of a bound state of a 2s exciton and a remote electron. Through a theoretical analysis of exciton-electron scattering, we show that the experimental spectra can only be explained by electron-mediated hybridization of 2s, 2p and interlayer excitons, leading to a new type of many-body state which we term Rydberg attractive polaron. We anticipate that this new understanding will ensure a more accurate assessment of the signatures of correlated electrons in two dimensional materials.