Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 80: Low-Dimensional Systems: Oxide Hetero-Interfaces

TT 80.4: Talk

Friday, March 24, 2017, 10:15–10:30, HSZ 103

2DEGs in binary oxides studied by ARPES: s vs. d orbitals and electron-phonon coupling — •Tobias C. Rödel^1,2,3, Franck Fortuna¹, François Bertran², Patrick Le Fèvre², and Andrés Felipe Santander-Syro¹ — ¹CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, 91405 Orsay, France — ²Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France — ³LPV, Physics and Material Science, University of Luxembourg, L-4422 Belvaux, Luxembourg

Two-dimensional electron gases (2DEGs) in SrTiO₃ attracted a lot of interest after the initially discovery at the LaAlO₃/SrTiO₃ interface due to its controversial origin and various different ground states (e.g. superconductivity, magnetism) which are tunable by a gate-voltage. We demonstrated that 2DEGs can be created in various other perovskite oxides using a simple Al-capping. This technique works also for non-perovskite systems and we studied the 2DEGs in the binary oxides TiO₂ and ZnO by angle-resolved photoelectron spectroscopy.
One major difference between the two systems is that the orbital character of the 2DEG is either s-type (ZnO) or d-type (TiO₂) and the resulting differences in the measured electronic structure of the 2DEG will be discussed. Recently, electron-phonon coupling in the 2DEG in SrTiO₃ was the focus of various studies. Similar to SrTiO₃, the transition from a polaron gas to a Fermi liquid can be observed in the two binary oxides depending on the charge carrier density. We will focus on the characterization of electron-phonon coupling for high charge densities.