Two-dimensional plasmonic polarons in n -doped monolayer MoS2

We report experimental and theoretical evidence of strong electron-plasmon interaction in $n$-doped single-layer ${\mathrm{MoS}}₂$. Angle-resolved photoemission spectroscopy measurements reveal the emergence of distinctive signatures of polaronic coupling in the electron spectral function. Calculations based on many-body perturbation theory illustrate that electronic coupling to two-dimensional carrier plasmons provides an exhaustive explanation of the experimental spectral features and their energies. These results constitute compelling evidence of the formation of plasmon-induced polaronic quasiparticles, suggesting that highly doped transition-metal dichalcogenides may provide a new platform to explore strong-coupling phenomena between electrons and plasmons in two dimensions.