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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 49.1: Talk
Friday, March 22, 2024, 09:30–09:45, H 0104
High-mobility two-dimensional electron gases based on strain engineered ferroelectric SrTiO3 thin films — •Ruchi Tomar1, Tatiana Kuznetsova2, Srijani Mallik1, Luis M. Vicente-Arche1, Fernando Gallego1, Maximilien Cazayous3, Roman Engel-Herbert2,4, and Manuel Bibes1 — 1Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France. — 2Pennsyvlania State University, University Park, PA 16802, USA. — 3Laboratoire Matériaux et Phénomènes Quantiques (UMR 7162 CNRS), Université de Paris, 75205 Paris Cedex 13, France. — 4Paul Drude Institute for Solid State Electronics, Leibniz Institute within Forschungsverbund Berlin eV, Hausvogteiplatz 5-7, 10117, Berlin, Germany.
Two-dimensional electron gases (2DEGs) based on the quantum paraelectric SrTiO3 display fascinating properties such as large electron mobilities, superconductivity, and efficient spin-charge interconversion owing to their Rashba spin-orbit coupling. Here, we use oxide molecular beam epitaxy to grow high-quality strain-engineered SrTiO3 films that are ferroelectric up to 170 K. We then generate a 2DEG by sputtering a thin Al layer and demonstrate an increase in mobilities compared to earlier literature. Furthermore, through Raman spectroscopy and magneto-transport measurements, we show that the ferroelectric character is retained after 2DEG formation. These results thus qualify our samples as ferroelectric 2DEGs up to temperatures well above previous results based on Ca-SrTiO3 substrates, opening the way towards ferroelectric 2DEGs operating at room temperature.
Keywords: two-dimensional electron gas; Epitaxial strain; Ferroelectricity; Raman spectroscopy