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MA: Fachverband Magnetismus
MA 49: SrTiO3: A Versatile Material from Bulk Quantum Paraelectric to 2D Superconductor III (joint session TT/KFM/MA/O)
MA 49.11: Vortrag
Freitag, 22. März 2024, 12:15–12:30, H 0104
Tunable 2D Electron- and 2D Hole States Observed at Fe/SrTiO3 Interfaces — •Pia Maria Düring1, Paul Rosenberger1,2, Lutz Baumgarten3, Fatima Alarab4, Frank Lechermann5, Vladimir N. Strocov4, and Martina Müller1 — 1FB Physik, Universität Konstanz, 78457 Konstanz — 2TU Dortmund, 44221 Dortmund — 3FZ Jülich, PGI-6, 52425 Jülich — 4PSI, SLS, CH-5232 Villingen — 5TP III, RU Bochum, 44780 Bochum
Oxide electronics provide the key concepts and materials for enhancing silicon-based semiconductor technologies with novel functionalities. However, a crucial property of semiconductor devices remains undisclosed in their oxide counterparts: the ability to set or even switch between negatively (n) charged electrons or positively (p) charged holes. Using resonant angle-resolved photoelectron spectroscopy, we provide direct evidence for individually emerging n- or p-type 2D band dispersions in SrTiO3 (STO)-based heterostructures [1]. The key to setting the carrier character is the oxidation state of a Fe-based interface layer: For Fe and FeO, hole bands emerge in the empty band gap region of STO, while for Fe3O4 overlayers, an 2D electron system (2DES) is formed. Unexpected oxygen vacancy characteristics arise for the hole-type interfaces, which as of yet had been exclusively assigned to the emergence of 2DESs. In general, this study unveils the potential to seamlessly alter the conductivity type at STO interfaces by manipulating the oxidation state of a redox overlayer.
[1] P. M. Düring et al., Adv. Mater. (accepted)
Keywords: 2D electron gases; 2D hole gases; oxide interfaces; Resonant ARPES; 2D Material