Electron energy-loss spectroscopy of UHV-cleaved NiO (100) surfaces

Electron energy-loss spectroscopy of ∼ 200 eV electrons has been applied to the study of the electronic states of clean NiO (100) surfaces. Initial attempt has been made on the identification of observed peaks, and they are attributed to the one-electronic transitions (O 2- 2 p → Ni 2+ 3 d , 4 s and 4 p ; Ni 2+ 3 d → 4 p , 3 p → 3 d and 4 s ), and the collective excitations (bulk plasmons of O 2- 2 p , Ni 2+ 3 d electrons, and coupled 2 p and 3 d electrons).