Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Focus Session: Surfaces and Interfaces of (Incipient) Ferroelectrics (joint session O/KFM)

O 44.3: Vortrag

Mittwoch, 7. September 2022, 16:00–16:15, H3

Influence of Nb dopants on the polarization and screening on cleaved SrTiO₃(001) surfaces — •Igor Sokolović¹, Alexander Hoheneder¹, Jesus Redondo², Dominik Wrana², Michael Schmid¹, Ulrike Diebold¹, and Martin Setvín² — ¹Institute of Applied Physics, TU Wien, Vienna, Austria — ²Faculty of Physics and Mathematics, Charles University, Prague, Czech Republic

The incipient ferroelectric SrTiO₃ can turn ferroelectric even at room temperature under the application of strain, and this quantum phase transition can be utilized to cleave SrTiO₃ single crystals that otherwise posses no preferable cleavage planes [1]. This cleaving procedure creates truly bulk-terminated SrTiO₃(001) surfaces that come the closest to being pristine [2]. In this talk, I will present how the SrO- and TiO₂-terminated surface domains of opposite polarity can be influenced by the small changes in the amounts of Nb doping. The cleaved SrTiO₃(001) surfaces with varying Nb doping levels were systematically studied with atomic resolution using noncontact atomic force microscopy (ncAFM) and scanning tunneling microscopy (STM). It was observed that Nb doping does not affect the magnitude of the strain-induced polarization, yet still significantly affects the morphology, the electronic structure, and the domain-wall structure on cleaved SrTiO₃(001) surfaces. Beside demonstrating the interplay between the domain distribution and electrostatic screening, these results show how the properties of these heterogeneous surfaces can be tuned.

[1] Sokolović et al., Phys. Rev. Mater. 3, 034407 (2019)

[2] Sokolović et al., Phys. Rev. B 103, L241406 (2021).