Probing the bulk plasmon continuum of layered materials through electron energy loss spectroscopy in a reflection geometry

Article

关键词: SURFACE-PLASMONS;    DIELECTRIC RESPONSE;    CHARGE EXCITATIONS;    STRATIFIED MEDIUM;    SUPERLATTICE;    SCATTERING;    GAS;    ELECTRODYNAMICS;    FLUCTUATIONS;   

DOI  :  10.1103/PhysRevB.106.155152

来源: SCIE

【 摘 要 】

A periodic arrangement of two-dimensional (2D) conducting planes is known to host a (bulk) plasmon dispersion that interpolates between the typical, gapped behavior of three-dimensional (3D) metals and a gapless, acoustic regime as a function of the out-of-plane wave vector. The semi-infinite system-the configuration relevant to electron energy loss spectroscopy (EELS) in a reflection geometry, as in high-resolution EELS (HREELS)-is known to host a surface plasmon that ceases to propagate below a cutoff wave vector. As the f-sum rule requires a finite response whether there exist sharp excitations, we demonstrate that what remains in the surface loss function-the material response probed by HREELS-is the contribution from the (bulk) plasmon of the infinite system. We provide a one-to-one mapping between the plasmon continuum and the spectral weight in the surface loss function. In light of this result, we suggest that HREELS be considered a long-wavelength probe of the plasmon continuum in layered materials.

【 授权许可】

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