Advances in momentum-resolved EELS of phonons, excitons and plasmons in 2D materials and their heterostructures
C. Elgvin1, F.S. Hage1, Ø. Prytz1, K. Elyas2, K. Hölich2, C.T. Koch3 and H.C. Nerl3
Published in:
Phys. Rev. Materials, vol. 10, no. 2, pp. 020201, doi:10.1103/8wwb-lxk2 (2026).
Abstract:
Functional nanomaterials, including two-dimensional (2D) materials and their heterostructures, are expected to impact fields ranging from catalysis and optoelectronics to nanophotonics. To realize their potential, ex- perimental approaches need to be developed to characterize the combined materials and their components. Techniques using fast electrons, such as electron energy-loss spectroscopy (EELS), probe phenomena over an unrivaled energy range with high resolution. In addition, momentum-resolved EELS simultaneously records energy and momentum transfer to the sample and thus generates 2D datasets for each beam position. This allows excitations that occur at large momentum transfer to be resolved, including those outside of the light cone and beyond the first Brillouin zone, all while retaining nanometer-sized spatial selectivity. Such capabilities are particularly important when probing phonons, plasmons, excitons, and their coupling in 2D materials and their heterostructures.
1 Department of Physics, University of Oslo, Oslo, Norway
2 Ferdinand-Braun-Institut (FBH), Berlin, Germany
3 Department of Physics and Center for the Science of Materials Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
Physics Subject Headings (PhySH):
Excitons; Magnons; Phonons; Plasmons; 2-dimensional systems; Graphene; Transition metal dichalcogenides; Electron energy loss spectroscopy; Electron microscopy
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