High resolution electron energy loss spectroscopy – A case study of MgB2

Abstract

We have setup a High Resolution Electron Energy Loss Spectrometer (HREELS) to study the low energy loss features in a solid. The energy resolution achieved so far in the spectrometer is 2.1 meV. Using this setup, we have studied the energy loss features of a conventional superconductor, MgB2. High energy resolution enabled to reveal many low energy loss features. These features can be associated to various phonon excitations in MgB2. These results indicate phonon excitations along with the photo-excitation process of photoemission as one possible reason for the asymmetry observed in the Mg 1s core level spectra found in earlier studies.