  We calculate electron energy loss spectra (EELS) for composite plasmonic
structures based on silicene and germanene. A continued-fraction expression for
the effective dielectric function is used to perform multiscale calculations of
EELS for both silicene and germanene-based structures on silver substrates. A
distinctive change in plasmonic response occurs for structures with a germanene
or silicene surface coating of more than three layers. These differences may be
exploited using spectroscopic characterization in order to determine if a
few-layer coating has been successfully fabricated.
