Phonon selection and interference in momentum-resolved electron energy loss spectroscopy

Fuente: arXiv
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Auteurs principaux: Pfeifer, Thomas W., Walker, Harrison A., Aller, Henry T., Graham, Samuel, Pantelides, Sokrates, Hachtel, Jordan A., Hopkins, Patrick E., Hoglund, Eric R.
Format: Preprint
Publié: 2025
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author Pfeifer, Thomas W.
Walker, Harrison A.
Aller, Henry T.
Graham, Samuel
Pantelides, Sokrates
Hachtel, Jordan A.
Hopkins, Patrick E.
Hoglund, Eric R.
author_facet Pfeifer, Thomas W.
Walker, Harrison A.
Aller, Henry T.
Graham, Samuel
Pantelides, Sokrates
Hachtel, Jordan A.
Hopkins, Patrick E.
Hoglund, Eric R.
contents As momentum-resolved Electron Energy Loss Spectroscopy (q-EELS) becomes more widely used for phonon measurements, better understanding of the intricacies of the acquired signal is necessary. Selection rules limit the allowed scattering, which may prohibit the appearance of specific phonon branches in some measurements. Simultaneous sampling of the lattice across all basis atoms also warrants a coherent treatment of phonons, which yields a reciprocal-space repeating unit cell that is larger than the standard Brillouin zone. We thus introduce the concept of the ``interferometric Brillouin zone'' where phonons are observed, which is closely related to the Dynamic Structure Factor. These effects follow from our new mathematical formalism for waves and vibrations, and we demonstrate calculations of q-EELS experiments using molecular dynamics and lattice dynamics. Results are compared to established q-EELS simulation methods in well-studied material systems, including the utilization of scattering selection rules to acquire a polarization-selective vibrational density of states. Finally, we note the analysis involved is directly applicable to any wave phenomena, such as plasmons or polaritons.
format Preprint
id arxiv_https___arxiv_org_abs_2503_09792
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Phonon selection and interference in momentum-resolved electron energy loss spectroscopy
Pfeifer, Thomas W.
Walker, Harrison A.
Aller, Henry T.
Graham, Samuel
Pantelides, Sokrates
Hachtel, Jordan A.
Hopkins, Patrick E.
Hoglund, Eric R.
Materials Science
As momentum-resolved Electron Energy Loss Spectroscopy (q-EELS) becomes more widely used for phonon measurements, better understanding of the intricacies of the acquired signal is necessary. Selection rules limit the allowed scattering, which may prohibit the appearance of specific phonon branches in some measurements. Simultaneous sampling of the lattice across all basis atoms also warrants a coherent treatment of phonons, which yields a reciprocal-space repeating unit cell that is larger than the standard Brillouin zone. We thus introduce the concept of the ``interferometric Brillouin zone'' where phonons are observed, which is closely related to the Dynamic Structure Factor. These effects follow from our new mathematical formalism for waves and vibrations, and we demonstrate calculations of q-EELS experiments using molecular dynamics and lattice dynamics. Results are compared to established q-EELS simulation methods in well-studied material systems, including the utilization of scattering selection rules to acquire a polarization-selective vibrational density of states. Finally, we note the analysis involved is directly applicable to any wave phenomena, such as plasmons or polaritons.
title Phonon selection and interference in momentum-resolved electron energy loss spectroscopy
topic Materials Science
url https://arxiv.org/abs/2503.09792