Dynamical Theory of Angle-Resolved Electron Energy Loss and Gain Spectroscopies of Phonons and Magnons in Transmission Electron Microscopy Including Multiple Scattering Effects

We present a method for computing angle-resolved electron energy loss and gain spectroscopies for phonon and magnon excitations in transmission electron microscopy. Fractional scattering intensities are derived from the temperature-dependent time autocorrelation of the auxiliary electron beam wave function. This method captures both single and multiple scattering processes, as well as dynamical diffraction effects, while remaining computationally efficient and easy to parallelize.