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Satellite structure in the photoemission spectra of MnO(100)

1991; American Physical Society; Volume: 43; Issue: 14 Linguagem: Inglês

10.1103/physrevb.43.11971

1095-3795

Shin-Puu Jeng, Robert J. Lad, Victor E. Henrich,

Electronic and Structural Properties of Oxides

The satellite structure in both core-level and valence-band photoemission spectra from single-crystal MnO(100) has been studied by using both x-ray photoemission spectra and resonant photoemission. Only very weak satellites are present in the Mn 2p core-level spectra, while no satellite structure is evident in the Mn 3p and 3s core-level spectra. The small intensity of the satellite peaks in MnO is consistent with the trend predicted by a recent ligand charge-transfer screening model; such screening is quite weak in MnO in comparison to the heavier transition-metal oxides. The valence-band spectrum, however, exhibits a stronger satellite peak than predicted by the model, and its origin has been uncertain. We have found that, while the satellite in the valence-band spectrum can be resonantly enhanced across the Mn 3p\ensuremath{\rightarrow}3d optical excitation threshold, its intensity depends strongly upon surface treatment. The satellite disappears with only 0.2--1-langmuir exposure of oxygen at 340 \ifmmode^\circ\else\textdegree\fi{}C, confirming that it is essentially a surface-related feature. We suggest that it is associated with point defects on the surface, presumably surface Mn vacancies.