Surface-Plasmon Excitation by Electron Tunneling

The role of various parameters in our theory of inelastic-electron tunneling associated with the excitation of surface plasmons is clarified in order to refute Duke's criticism. It is shown here that our theory involves only one adjustable parameter, which can be determined independently from the random-phase-approximation analysis of surface plasmons. Hence there are no adjustable parameters in fitting theory to experiment. We have fortified the claim of agreement between our theory and experiment by a calculation of the background, and a detailed comparison with raw experimental data. Predictions from both the inelastic surface-plasmon excitation model and the electron-bulk-plasmon interaction model are compared. The surface-plasmon excitation model provides a far superior fit to the experimental data.