Regensburg 2022 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 7: Focus Session: Defects and Interfaces in Multiferroics 2

KFM 7.3: Talk

Monday, September 5, 2022, 15:50–16:10, H5

Electric-field control of oxygen defects and local transport properties in ErMnO₃ — •Jiali He¹, Ursula Ludacka¹, Donald M. Evans¹, Theodor S. Holstad¹, Erik D. Roede¹, Kasper A. Hunnestad¹, Konstantin Shapovalov², Zewu Yan^3,4, Edith Bourret⁴, Antonius T. J. van Helvoort¹, Sverre M. Selbach¹, and Dennis Meier¹ — ¹NTNU Norwegian University of Science and Technology, Norway — ²Institute of Materials Science of Barcelona, Spain — ³ETH Zurich, Switzerland — ⁴Lawrence Berkeley National Laboratory, USA

The electronic properties of complex oxides can be tuned via oxygen defects, offering intriguing opportunities for controlling conductivity. Recently, anti-Frenkel defects moved into focus for minimally invasive property engineering, and their creation makes it possible to adjust the electronic properties without long-range ionic migration or stoichiometry changes. Here, we present a detailed analysis of the electric-field-driven formation and time-voltage-dependent evolution of anti-Frenkel defects in hexagonal ErMnO₃. By combining atomic force microscopy and scanning electron microscopy, we investigate the local electronic transport properties associated with the written defects, complemented by numerical simulations. The study reveals that oxygen interstitial - vacancy pairs can be split under an applied electric field. This splitting leads to spatially separated and well-defined vacancy- and interstitial-rich regions, forming a bipolar nanoscale junction. The results provide new insight into the electric-field-driven ionic migration in ErMnO₃ and defects physics in functional oxides.