Dresden 2026 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

DS: Fachverband Dünne Schichten

DS 20: Poster

DS 20.26: Poster

Thursday, March 12, 2026, 18:30–20:30, P2

Formation and protection of two-dimensional electron gases at SrTiO3 interfaces via redox reactions — •Shi-Hui Liu, Georg Hoffmann, and Roman Engel-Herbert — Paul-Drude-Institut für Festkörperelektroni, Berlin, Germany

Strontium titanate (SrTiO3) has been the workhorse for development of new physical phenomena over decades. Recently, new momentum was generated when the formation of a two-dimensional electron gas (2DEG) via oxygen scavenging effect at the SrTiO3/AlOx interface was observed, i.e. oxidation of the deposited metal-layer upon reduction of the SrTiO3 [1]. However, depending on the Al layer thickness, these 2DEGs degrade over time due to diffusion of oxygen from the gas phase through the AlOx layer refilling the vacancies.

In this work, amorphous aluminum layers with thicknesses ranging from 0.5 to 2.5 nm were deposited on TiO2-terminated SrTiO3 (001) substrates using molecular beam epitaxy. The complementary methods of in-situ x-ray photoelectron spectroscopy, and capacitance-voltage measurements were performed to monitor the interfacial redox reaction and to identify the spatially confined conduction channel, respectively. Since the 2DEG remains stable only for a limited time within an optimum aluminum layer thickness, strategies for protecting and stabilizing the 2DEG will be pointed out.

References: [1] L. M. Vicente-Arche et al., Phys. Rev. Mater. 5, 064005 (2021).

Keywords: redox reactions; oxide mbe; two-dimensional electron gas; strontium titanate; in-situ x-ray photoelectron spectroscopy