Loss for photoemission versus gain for Auger: Direct experimental evidence of crystal-field splitting and charge transfer in photoelectron spectroscopy

Abstract

We find a new 5 eV satellite in the Ti 1s photoelectron spectrum of the transition-metal oxide SrTiO 3 . This satellite appears in addition to the well-studied 13 eV structure that is typically associated with the Ti 2p core line. We give direct experimental evidence that the presence of two satellites is due to the crystal-field splitting of the metal 3d orbitals. They originate from ligand 2p t 2g → metal 3d t 2g and ligand 2p e g → metal 3d e g monopole charge-transfer excitations within the sudden approximation of quantum mechanics. This assignment is made by the energetics of the resonant and high-energy threshold behaviors of the Ti K-L 2 L 3 Auger decay that follows Ti 1s photo-ionization.

Local atomic geometry and Ti 1s near-edge spectra in PbTiO3 and SrTiO3

“…AIMD simulations SrTiO 3 at room temperature give fluctuations σ(t of selection rules have also been found that allow s → s transitions in x-ray absorption because of lattice vibrations, which has been reported by others [46][47][48][49]. We also note that the exaggerated intensity of the features near 4975 eV in SrTiO 3 could result from the BSE calculations failure to account for charge-transfer processes that should appear like more effect screening of the Ti 1s hole when the excited core electrons leaves the Ti site [50].…”

Role of Oxygen Deposition Pressure in the Formation of Ti Defect States in TiO2(001) Anatase Thin Films

“…) and the four satellites typical of the Ti 2p peak in titanates such as SrTiO 3 . 66 Two additional peaks were added on the low-energy side at the foot of the two main peaks to consider Ti 3+ suboxides (see Figure 5a and more details in Figure S3). The ratio of the area of the peaks Ti 3/2 4+ (blue) and Ti 3/2 3+ (red) is measured for the different samples and displayed in Figure 5c (black curve) as a function of the growth oxygen pressure.…”

Hard X-ray PhotoElectron Spectroscopy of transition metal oxides: Bulk compounds and device-ready metal-oxide interfaces

“…Noticeably, a recent study of the Ti 1s core level spectrum of SrTiO 3 has shown the presence of a satellite located at a distance of 5 eV on the high binding energy side of the Ti 1s peak, in addition to the well-studied structure at 13 eV that is typically observed for the Ti 2p core line. [41] This work demonstrates that the presence of the satellites in the Ti 1s spectrum originates from the crystal-field splitting of the metal 3d orbitals and ligand 2p-metal 3d charge transfer among Ti and the surrounding oxygen ions.…”