Fig. 3. Origin of magnetophonon scattering effect.

(A and B) The vector of induced dipole moment [P(0) and P(H)] is rotated by magnetic field from 0° to θ, leading to the direction of the maximum differential scattering cross sections [E(0) and E(H)] rotating at an angle of θ. φ is the angle between the dipole moment (P) and the scattering direction (R); S represents the Poynting vector; E is the electric field vector that is perpendicular to R in the plane comprising R and P. E(0) and E(H) are maximized when φ = 90^°. (C) All experimental and corresponding calculation (3D color distributions, g = 4; fig. S9C) results of the $A_{\mathrm{g}}^3$ mode of bulk CrI₃ versus magnetic field and polarization angle, which are well consistent. The intensity ratio of the $A_{\mathrm{g}}^3$ to the $E_{\mathrm{g}}^4$ mode is used to eliminate the system disturbance in the fitting. (D) Corresponding calculation results of the $A_{\mathrm{g}}^3$ mode of bulk CrI₃ as a function of parameter g, magnetic field, and polarization angle.