Optical properties and plasmon dispersion in epitaxial (SN)_x by electron energy loss spectroscopy

Abstract

Wavevector dependent electron energy loss spectra of epitaxial films of (SN), between 0 to 30 eV up to wave vector transfers of 1 A-l are measured for k parallel and perpendicular to the chain axis. The optical constants el, e2 and the reflectivity R are derived by a Kramers-Kronig analysis for zero wavevector. Peak positions in R agree with optical measurements. A change in the dispersion of the bulk plasmon of the conduction electrons is attributed to the interference with free-electron-like single particle excitations.

Polysulfur nitride - a metallic, superconducting polymer

“…0.15 eV lower for epitaxial films than those determined from (SN)X single crystals. 113 Stolz et al also found that the plasmon energy values derived by electron energy-loss spectroscopy on (SN)X epitaxial films are lower than the comparable values for single crystals. 113 This work also indicates differences between the lattice and/or defect structure of (SN)X single crystals and epitaxial films.…”

“…The excellent agreement between the calculated and experimental plasmon energy as a function of 8 in terms of R= 1.9 is additional convincing evidence that (SN)X is effectively an anisotropic threedimensional material. 112 Plasmon dispersion and optical properties of epitaxially grown (SN)X films have been studied by Stolz et al 113 By using a 30-keV electron beam, energy loss spectrum peaks for (SN)X at room temperature at 1.7, 2.4, 4.4, 6.2, 8.2, 12.0, and 22. surements on single crystals of (SN)X is about 1.5 eV. Plasmon energy values obtained by reflectivity are ca.…”