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O: Fachverband Oberflächenphysik
O 92: Oxide and Insulator Surfaces II: Structure, Epitaxy and Growth
O 92.9: Vortrag
Freitag, 31. März 2023, 12:30–12:45, CHE 91
2D electron gas and interdiffusion processes at the EuO/SrTiO3(001) interface — •Anne Oelschläger, Hannes Herrmann, Stefan Förster, and Wolf Widdra — Martin-Luther-Universität Halle-Wittenberg, Institute of Physics, 06120 Halle, Germany
The deposition of metallic europium (Eu) on SrTiO3(001) (STO) creates a two-dimensional electron gas (2DEG) and concomitant Ti3+-O2-vacancy complexes [1]. Here we study this interface by HREELS, XPS and LEED. The phonon spectra are dominated by the dipole-active surface phonon polaritons of STO. They show a prominent broadening in the presence of the 2DEG due to strong electron-phonon coupling.
Upon annealing to 1020 K, the Ti3+ related photoemission lines as well as the phonon broadening vanish. We assign these changes to diffusion of oxygen from the bulk to the EuO/STO interface. Finally, the intensity ratio of Sr3p and Ti2p core levels indicates a diffusion of Ti to the europium oxide (EuO) layer, i.e. formation of EuTiO3.
[1] P. Lömker et al. Phys. Rev. Mater. 1, 062001(R), 2017