Fig. 3
From: Tuning the Fröhlich exciton-phonon scattering in monolayer MoS2
Impurity assisted Fröhlich scattering. a Plot of the matrix element of the exciton-phonon Fröhlich interaction in dependence of the product of the phonon wave vector q and the exciton radius a0. See Supplementary Note 2 for details. For the intrinsic first-order process qa0 ≈ 0.02, while in the impurity assisted process q can take arbitrary values. The qa0 dependence of |HFI|2 is qualitatively independent of a0. b Feynman diagrams for the scattering of a photon with frequency ω and momentum k from initial state i to final state s by emitting a phonon with frequency Ω and momentum q. Upper panel: intrinsic first-order Raman process. Lower panel: second-order process involving elastic scattering with an impurity. HeR denotes the electron-radiation interaction; HeL is the electron lattice interaction, which can be either DP or FI. He-i represents the electron-impurity interaction for the elastic scattering with momentum transfer q’. We show only one permutation of the interactions. c Resonant Raman intensities (Ei = 1.96 eV) for linear parallel polarization (êi = ês) for one whole rotation of the angle θ between êi,s and the crystal axes. Lower panel: amplitude of the E’ mode (yellow triangles). Fitted amplitudes are plotted as scatters. The line plots show the calculated polarization dependences of the intrinsic and the impurity-assisted exciton-LO phonon scattering processes (solid and dashed lines, respectively). Upper panel: amplitude of the TO mode of the silicon substrate used as a reference signal (Scatters: measured data, Line plot: simulated data). Spectra are shown in Supplementary Fig. 4
