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arXiv · 2508.07073

Theory of Momentum-Resolved Electron Energy-Loss Spectra of Coupled Phonon and Magnon Excitations

José Ángel Castellanos-Reyes·Ivan P. Miranda·Paul M. Zeiger·Anders Bergman·Ján Rusz
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Abstract

We develop a theory of momentum-resolved electron energy-loss spectra in the scanning transmission microscope (STEM-EELS) that captures the effects of coupled phonon and magnon excitations within a unified formalism, and apply it to body-centered cubic iron at 300 K. By advancing the Time Autocorrelation of Auxiliary Wavefunctions (TACAW) method to incorporate atomistic spin-lattice dynamics (ASLD), we simulate the EELS signal, including phonon-magnon interaction effects, dynamical diffraction, and multiple scattering. Our results reveal non-additive spectral features arising from phonon-magnon coupling, hybridization, and energy shifts, and further allow estimation of the electron dose required to detect magnon scattering under optimized detector conditions.

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José Ángel Castellanos-Reyes, Ivan P. Miranda, Paul M. Zeiger, Anders Bergman, Ján Rusz. 2025-08-09. Theory of Momentum-Resolved Electron Energy-Loss Spectra of Coupled Phonon and Magnon Excitations. https://arxiv.org/abs/2508.07073

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