Cation diffusion and hybridization effects at the Mn-GaSe(0001) reacted interface:Ab initiocalculations and soft x-ray electron spectroscopy studies

Abstract

The electronic properties of the Mn:GaSe interface, produced by evaporating Mn at room temperature on a ǫ-GaSe(0001) single crystal surface, have been studied by soft X-ray spectroscopies. Substitutional effects of Mn replacing Ga cations and Mn-Se hybridization effects are found both in core level and valence band photoemission spectra. The Mn cation valence state is probed by XAS measurements at the Mn L-edge, which indicate that Mn diffuses into the lattice as a Mn 2+ cation with negligible crystal field effects. The Mn spectral weight in the valence band is probed by resonant photoemission spectroscopy at the Mn L-edge, which also allowed an estimation of the charge transfer and Mott-Hubbard energies on the basis of impurity-cluster configuration-interaction model of the photoemission process. The charge transfer energy is found to scale with the energy gap of the system. Competing effects of Mn segregation on the surface have been identified, and the transition from the Mn diffusion through the surface to the segregation of metallic layers on the surface has been tracked by core-level photoemission.

Facile Synthesis of Yolk–Shell Mn3O4 Microspheres as a High-Performance Peroxymonosulfate Activator for Bisphenol A Degradation

“…Further exploring the specific BPA degradation mechanism of the system, we also determine the valence state changes of the Mn element in YS-Mn 3 O 4 before and after reaction by using XPS analysis. All Mn 2p 3/2 peaks can be separated into three peaks, which is assigned to Mn 4+ at 643.9 eV, Mn 3+ at 641.9 eV, and Mn 2+ at 640.7 eV. , According to the fitting results indicated in Table , the relative contents of Mn 4+ , Mn 3+ , and Mn 2+ are 12.8, 57, and 30.2%, respectively, before the reaction. In contrast, they become 21.9, 55.0, and 23.1%, respectively, after the reaction.…”