Multiplet XPS analysis of the Mn 2p for Mn₃O₄ thin films

Abstract

In this work, we performed a detailed analysis of the X-ray photoemission Spectroscopy (XPS) of the Mn 2p peak for Mn3O4(001) thin films. This is a challenging task since Mn3O4 is composed of two different cations, Mn2+ at tetrahedral and Mn3+ at octahedral sites, which both contribute to the XPS spectra. The oxide spectra consist of many multiplets arising from the angular momentum coupling of the open Mn 2p and 3d shells, thus increasing the spectrums' complexity. Moreover, the energy spacing and intensities of the different multiplets also reflect the covalent mixing between Mn 3d and O 2p shells. However, we show that a detailed analysis, which provides relevant information about the cations in the oxide structure, is possible. We prepared experimentally different Mn3O4 films on Au(111), and their structure was monitored with the diffraction pattern obtained with Low-Energy Electron Diffraction (LEED). The Mn 2p spectra were fit, guided by cluster model theoretical predictions, and checked for films prepared at different oxygen partial pressures. Therefore, we could observe the Mn2+ and Mn3+ cations' relative concentration in the Mn 2p mains peaks.