Invited Paper SS+2D+AP+AS+OX+SE-ThA8
Noncontact AFM on Oxide Surfaces: Challenges and Opportunities

Thursday, October 24, 2019, 4:40 pm, Room A220-221

Recent development of the noncontact atomic force microscopy (nc-AFM) has opened new possibilities in different fields – imaging of organic molecules [1], controlling the charge state of adsorbed species [2], or enhanced chemical resolution of surface atoms [3]. I will focus on the emerging possibilities and opportunities in the field of oxide surfaces and their surface chemistry.

The limits of atomic resolution will be illustrated on clean and water-exposed binary oxides like TiO₂, In₂O₃ or iron oxides. The enhanced chemical resolution of nc-AFM offers a unique opportunity for approaching complex materials with ternary chemical composition. This will be demonstrated on bulk-terminated perovskites SrTiO₃ and KTaO₃. A dedicated cleaving procedure [4,5] allows preparing flat regions terminated by domains of SrO/TiO₂ (or KO/TaO₂) with a well-defined atomic structure. The surface stability, point defects, electronic structure, and chemical properties of such surfaces will be discussed and linked to the incipient-ferroelectric character of these materials.

[1] Gross, L.; Mohn, F.; Moll, N.; Liljeroth, P.; Meyer, G., Science 2009, 325, 1110

[2] Gross, L.; Mohn, F.; Liljeroth, P.; Repp, J.; Giessibl, F. J.; Meyer, G., Science 2009,324, 1428

[3] Sugimoto, Y.; Pou, P.; Abe, M.; Jelinek, P.; Perez, R.; Morita, S.; Custance, O., Nature 2007,446, 64

[4] I. Sokolovic, M. Schmid, U. Diebold, M. Setvin, Phys. Rev. Materials 3, 034407 (2019)

[5] M. Setvin, M. Reticcioli, F. Poelzleitner, J. Hulva, M. Schmid, L. A. Boatner, C. Franchini, U. Diebold, Science 359, 572-575 (2018)