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O: Fachverband Oberflächenphysik
O 92: Oxide and Insulator Surfaces II: Structure, Epitaxy and Growth
O 92.8: Vortrag
Freitag, 31. März 2023, 12:15–12:30, CHE 91
Electron-phonon coupling for the 2D electron gas at EuO/KTaO3(001) studied by HREELS — •Hannes Herrmann, Anne Oelschäger, and Wolf Widdra — Martin-Luther-Universität Halle-Wittenberg, Institute of Physics, 06120 Halle, Germany
Recent studies at the KTaO3(111) surface revealed a 2D electron gas (2DEG) with much higher charge carrier density than in SrTiO3-based heterostructures [1]. Similar 2DEGs with lower charge carrier densities could be obtained on the (011) and (001) surfaces [2].
In this work, we study surface plasmon polaritons (SPP) and their coupling to a 2DEG with high-resolution electron energy loss spectroscopy (HREELS). By evaporating Eu on top of KTaO3(001), a 2DEG is initiated resulting in a pronounced asymmetric SPP line shape and extreme broadening compared to the phonons of the clean surface. The line shape will be analysed in terms of a strong coupling of the SPP with the 2DEG. The response can be described by a two-layer model with a 2D Drude-like response with frequency-dependent electronic mobility on top of a bulk-like KTaO3.
[1] A. F. Santander-Syro, C. Bareille, F. Fortuna and M. J. Rozenberg, Phys.Rev. B 86, 121107 (2012)
[2] P. D. C. King, R. H. He, T. Eknapakul and W. Meevasana, Phys. Rev. Lett. 108.117602 (2012)